Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting t...Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.展开更多
Methane dehydroaromatization(MDA)presents a promising carbon-neutral pathway for benzene,toluene,and xylene(BTX)production,alternative to petroleumderived routes.Elucidating the regulatory mechanisms of Brønsted ...Methane dehydroaromatization(MDA)presents a promising carbon-neutral pathway for benzene,toluene,and xylene(BTX)production,alternative to petroleumderived routes.Elucidating the regulatory mechanisms of Brønsted acid site(BAS)strength on reaction pathways,alongside the spatial proximity effects between BAS and Mo active sites in bifunctional synergy,remains a critical scientific challenge in catalyst design.This study systematically tunes both BAS strength(via isomorphous metal substitution)and Mo-BAS spatial proximity in zeolites,integrating MDA catalytic evaluations with density functional theory(DFT)calculations to dissect their individual contributions.Strongly acidic BAS catalysts(compared to moderately acidic Fe/Ga-substituted counterparts)exhibit superior performance,evidenced by enhanced aromatic yields.Conversely,weakly acidic Bsubstituted zeolites demonstrate optimal mono-/bifunctional synergy,outperforming moderate-acid systems.DFT results reveal that acid strength dictates C−H activation mechanisms by modulating the energy barriers of rate-determining steps.While Al-zeolites deliver the highest activity,B-substituted systems display unique potential for mechanistic investigations.Spatial proximity analysis indicates that micrometer-scale Mo-BAS distances hinder effective synergy due to exceeding electron interaction and mass transfer limits,whereas nanometer-scale proximity enhances activity(via accelerated intermediate transport)and suppresses coke formation.These findings establish a theoretical framework for rationalizing zeolite catalyst optimization through BAS property engineering and spatial control of Mo-BAS cooperation,providing actionable guidelines for designing next-generation MDA catalysts.展开更多
Catalytic decomposition of methane,which produces high-purity hydrogen and high-value-added carbon nanomaterials,has shown considerable potential for development and is expected to yield significant economic benefits ...Catalytic decomposition of methane,which produces high-purity hydrogen and high-value-added carbon nanomaterials,has shown considerable potential for development and is expected to yield significant economic benefits in the future.However,designing catalysts that simultaneously exhibit high activity and long-term stability remains a significant challenge.Tuning the catalyst’s structure and electronic properties is an effective strategy for enhancing the reaction performance.In this work,a series of NixZr/ZSM-5 catalysts were prepared using the incipient wetness impregnation method,and the effect of Zr loadings on catalyst properties and performance was systematically investigated.The calcined and reduced catalysts were characterized by low-temperature N_(2)adsorption-desorption,XRD,SEM,H_(2)-TPR and XPS.The results showed that the addition of Zr significantly increased the specific surface area of the catalyst and reduced the metal particle size.Smaller NiO particles were found to enter the pores of the HZSM-5 support,and electronic interactions between NiO and ZrO_(2)markedly enhanced the metal-support interaction.The catalyst exhibited optimal catalytic performance at a Zr loading of 5%,achieving a maximum methane conversion of 68%at 625℃,maintaining activity for 900 min,and delivering a carbon yield of 1927%.Further increasing the Zr loading yielded only limited improvements in catalytic performance.Characterization of the spent catalysts and carbon products via TEM,Raman spectroscopy,and TGA revealed that the introduction of ZrO_(2)reduced metal sintering and promoted a shift in carbon nanofibers growth mode from tip-growth to base-growth.The mechanism of base-growth enabled the catalyst to maintain reaction activity for an extended period.展开更多
Rice fields are one of the largest sources of methane(CH4),a potent greenhouse gas contributing significantly to global warming.Elucidating the underlying mechanisms and mitigating CH4 emissions from paddy fields is c...Rice fields are one of the largest sources of methane(CH4),a potent greenhouse gas contributing significantly to global warming.Elucidating the underlying mechanisms and mitigating CH4 emissions from paddy fields is crucial for combating climate change while ensuring sustainable food production.This review investigates the biological processes governing CH4 generation in rice fields,focusing on how soil microorganisms generate CH4 under waterlogged,anaerobic conditions.It also explores the mechanisms by which CH4 escapes into the atmosphere through plant-mediated transport,diffusion,and ebullition.Several factors influencing CH4 emissions are discussed,including soil composition,water management,exogenous organic matter application,rice variety selection,and local climate conditions.Strategies that can be implemented to reduce CH4 emissions are assessed,such as alternate wetting and drying,urea deep placement,biochar application,optimized fertilizer application,and breeding of rice varieties with low CH4 emissions.Novel solutions,such as the enhancement of methane-consuming bacteria in soils using microbial-based approaches,are also explored.The importance of integrating innovative technologies,improved farming practices,and interdisciplinary research is emphasized to develop practical and scalable strategies for reducing CH4 emissions.By addressing these challenges,we can advance towards the attainment of sustainable agriculture and global climate goals.This review aims to serve as a comprehensive resource for researchers,policymakers,and practitioners seeking to understand and mitigate CH4 emissions from rice cultivation.展开更多
Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen micro...Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen microbiota in beef cattle and how microbes change after 3-NOP withdrawal have not been studied.This study investigated changes in rumen bacteria,archaea,and protozoa after ST and LT dietary supplementation and removal of 3-NOP using metataxonomic analysis.Results A total of 143 rumen samples were collected from two beef cattle studies with 3-NOP supplementation.The ST study(95 samples)used eight ruminally cannulated beef cattle in a 4×4 Latin square design with four 28-d of 3-NOP treatments[mg/kg of dry matter(DM)]:control:0,low:53,med:161,and high:345.The LT study(48 samples)was a completely randomized design with two 3-NOP treatments[control:0,and high:280 mg/kg of DM)fed for 112-d followed by a 16-d withdrawal(without 3-NOP).Bacterial and archaeal communities were significantly affected by 3-NOP supplementation but limited effects on protozoal communities were observed.Under ST supplementation,the relative abundances of Prevotella,Methanobrevibacter(Mbb.)ruminantium,Methanosphaera sp.ISO3-F5,and Entodinium were increased(Q<0.05),whereas those of Mbb.gottschalkii and Epidinium were decreased(Q<0.05)with 3-NOP supplementation.In LT study,relative abundances of Mbb.ruminantium,and Methanosphaera sp.Group5 were increased(Q<0.05),while those of Saccharofermentans and Mbb.gottschalkii were decreased(Q<0.05)with 3-NOP supplementation.Comparison between 3-NOP supplementation and the withdrawal revealed increased relative abundances of Clostridia UCG-014 and Oscillospiraceae NK4A214 group and decreased those of Eubacterium nodatum group and Methanosphaera sp.Group5(P<0.05)after 3-NOP withdrawal.Further comparison of rumen microbiota between control and 3-NOP withdrawal showed significantly higher(P=0.029)relative abundances of Eggerthellaceae DNF00809,p-1088-a5 gut group,and Family XII UCG-001 in control group while no significant differences were detected for archaea and protozoa.Microbial network analysis revealed that microbial interactions differed by both 3-NOP dose and durations.Conclusions Both ST and LT supplementation affected overall rumen microbial profile,with individual microbial groups responded to 3-NOP supplementation differently.After 3-NOP withdrawal,not all microbes showed recovery,indicating that the 3-NOP driven shifts were only partially reversible.These findings provide an understanding of the effects of 3-NOP on rumen microbial communities and their adaptability to methane mitigation strategies.展开更多
Directly burning methane for energy production wastes chemical potential and exacerbates CO_(2) emissions,while catalytic conversion into high-value fuel/chemicals provides economic and environmental sustainability.Ph...Directly burning methane for energy production wastes chemical potential and exacerbates CO_(2) emissions,while catalytic conversion into high-value fuel/chemicals provides economic and environmental sustainability.Photocatalytic CH_(4) conversion has emerged as a transformative technology,enabling selective oxidation under ambient conditions to directly synthesize value-added organic compounds.This addresses the dual challenges of climate mitigation and sustainable energy conversion.This review systematically examines the development of photocata lytic CH_(4) conversion,with three key dimensions.Firstly,we elucidate fundamental reaction mechanisms governing CH_(4) activation,emphasizing critical steps such as C-H bond scission via charge transfer,intermediate stabilization,and product desorption kinetics.Subsequently,we classify emerging photocata lytic pathways(partial oxidation,coupling,and reforming)and analyze material innovations.Finally,the challenges of the current photocata lytic CH_(4)conversion system and catalyst development were discussed,and perspectives were presented.The overarching objective of this work is to provide a comprehensive roadmap for the development of solardriven CH_(4) conversion systems that are aligned with global carbon neutrality goals.展开更多
Significant differences exist between deep and medium-shallow coalbed methane(CBM)reservoirs.The unclear understanding of flowback and production behavior severely constrains the development of deep CBM resources.To a...Significant differences exist between deep and medium-shallow coalbed methane(CBM)reservoirs.The unclear understanding of flowback and production behavior severely constrains the development of deep CBM resources.To address this challenge,guided by the gas-liquid two-phase flow theory in ultra-low permeability reservoirs,and integrating theoretical analysis,numerical simulation,and insights from production practices,this study classifies the flowback and production stages of deep CBM well considering the Daning-Jixian Block,Eastern Ordos Basin as a representative case.We summarize the flowback characteristics for each stage and establish a standard flowback production type curve,aiming to guide field operations.The results indicate that:(a)The production process of deep CBM horizontal wells can be divided into five distinct stages:initial single-phase water dewatering stage,initial gas appearance to peak water production stage,gas breakthrough to peak gas production stage,stable production and decline stage,and low-rate production stage.(b)Based on reservoir energy,two standard type curves for horizontal well flowback production are established:the‘Sufficient Reservoir Energy’type and the‘Insufficient Reservoir Energy’type.The former achieves a higher initial gas rate(up to 12×10^(4)m^(3)/d)but exhibits poorer stability,while the latter achieves a lower stable rate(up to 8×10^(4)m^(3)/d)but demonstrates stronger stability.Numerical simulation confirms these behavioral patterns and reveals the underlying mechanisms related to the effectively drained area where pressure is significantly depleted.The findings from this study have guided the flowback production operations in 53 deep CBM wells with positive results,demonstrating high potential for broad application.展开更多
The traditional ammonia synthesis via the Haber–Bosch process requires large consumption of highpurity H_(2) and causes significant carbon emissions owing to the energy-intensive and complex hydrogen production steps...The traditional ammonia synthesis via the Haber–Bosch process requires large consumption of highpurity H_(2) and causes significant carbon emissions owing to the energy-intensive and complex hydrogen production steps conducted under harsh reaction conditions.Herein,we report a cyclic catalytic process for the production of NH_(3) by directly utilizing earth-abundant CH_(4) as a hydrogen source for N_(2) hydrogenation while simultaneously co-producing H_(2) over an alumina-supported iron catalyst(Fe/Al_(2)O_(3)).It achieves exceptional productivities of 2300μmol g^(-1)h^(-1)for NH_(3) and 400 mmol g^(-1)h^(-1)for H_(2) at700℃.By eliminating the coke that results from CH_(4) pyrolysis through a reaction with the greenhouse gas CO_(2) to produce valuable CO,we establish an atom-economic cyclic catalytic process while producing a CO stream intrinsically separated in the regeneration step.Mechanistic investigations indicate that the iron species in Fe/Al_(2) O_(3) serve as tri-functional active sites for CH_(4) pyrolysis,N_(2) hydrogenation,and coke elimination to produce CO,thus enabling an efficient and environmentally friendly cyclic catalytic process.展开更多
The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environ...The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environmental purification.A major challenge in this field is the chemical inertness of methane and the strong oxidizing nature of photogenerated holes,which can lead to over-oxidation and reduced selectivity and efficiency.To address these issues,we have developed a sodium-doped zinc oxide(Na-ZnO) modified with cobalt oxide(CoO) catalyst.This catalyst has demonstrated excellent performance in converting methane to low alcohols,achieving a yield of 130 μmol g^(-1)h^(-1) and a selectivity of up to 96 %.The doping of Na in ZnO significantly enhances methane adsorption,while the surface-modified CoO effectively captures photogenerated holes,activates water molecules,and uses hydroxyl radicals to activate methane,thus controlling the dehydrogenation degree of methane and preventing the formation of over-oxidized products.This strategy has successfully improved the efficiency and selectivity of photocatalytic methane oxidation to low alcohols,offering a new perspective for the application of photocatalytic technology in energy and environmental fields.展开更多
Sintering and coking are critical barriers to achieving high performance in dry reforming of methane(DRM)catalysts.A finely dispersed and thermostable Ni-based catalyst is the key to address these issues.By leveraging...Sintering and coking are critical barriers to achieving high performance in dry reforming of methane(DRM)catalysts.A finely dispersed and thermostable Ni-based catalyst is the key to address these issues.By leveraging the intrinsic superiorities of high-entropy oxides in high-temperature stability and low atomic diffusivity,in this study,a highly dispersed Ni-based catalyst is synthesized via an entropycontrolled exsolution of active components.By increasing the number of transition-metal elements in spinel oxides,the active metalsupport interaction(MSI)can be continuously strengthened,which controls the exsolution and thermal stability of Ni-based active metal in harsh reaction conditions of DRM.An optimized medium-entropy spinel(Mg_(0.4)Ni_(0.2)Co_(0.2)Zn_(0.2))Al_(2)O_(4)with the exsolution of finely dispersed Ni–Co nanoparticles displayed superior activity and stability in thermal DRM at 800°C and photothermal DRM.This entropy-controlled MSI and exsolution principle provides a significant strategy for designing robust catalysts resistant to sintering and coking for high-temperature reactions like DRM in thermal and photothermal systems.展开更多
In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leadi...In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leading to suboptimal reservoir performance.Currently,there is no well-established method for accurately evaluating the effectiveness of such stimulation.This study introduces,for the first time,the concept of the Fracture Network Bridging Coefficient(FNBC)as a novel metric to assess stimulation performance.By quantitatively coupling the proportions of unstimulated and overstimulated volumes,the FNBC effectively characterizes the connectivity and efficiency of the fracture network.A background grid calibration method is developed to quantify the stage-controlled volume,effectively stimulated volume,unstimulated volume,and repeatedly stimulated volume among different stages of horizontal wells.Furthermore,an optimization model is constructed by taking the FNBC as the objective function and the fracturing injection rate and fluid volume as optimization variables.The Simultaneous Perturbation Stochastic Approximation(SPSA)algorithm is employed to iteratively perturb and optimize these variables,progressively improving the FNBC until the optimal displacement rate and fluid volume corresponding to the maximum FNBC are obtained.Field application in a typical CBM multistage fractured horizontal well in China demonstrates that the FNBC increased from 0.358 to 0.539(a 50.6% improvement),with the injection rate rising from 16 m^(3)/min to 24 m^(3)/min and the average fluid volume per stage increasing from 2490 m^(3) to 3192 m^(3),significantly enhancing the stimulation effectiveness.This research provides theoretical support for designing high-efficiency stimulation strategies in unconventional reservoirs under dynamic limits.展开更多
Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making ...Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making it a promising target for CH_(4) mitigation.This study aimed to identify and validate plant-derived inhibitors by using molecular docking to screen compounds with strong binding affinity to the F430 active site of MCR and assessing their efficacy in reducing CH_(4) emissions.Results Molecular docking analysis identified salvianolic acid C(SAC)as a potent inhibitor of MCR,showing a strong binding affinity to the F430 active site(binding energy:-8.2 kcal/mol).Enzymatic inhibition assays confirmed its inhibitory effect,with a half-maximal inhibitory concentration(IC50)of 692.3μmol/L.In vitro rumen fermentation experiments demonstrated that SAC supplementation(1.5 mg/g DM)significantly reduced CH_(4)production(P<0.01)without negatively affecting major fermentation parameters.Microbial community analysis using 16S rRNA sequencing and metagenomics revealed that SAC selectively altered the rumen microbiota,increasing the relative abundance of Bacteroidota while significantly reducing Methanobrevibacter(P=0.04).Moreover,metagenomic analysis showed the downregulation of key methanogenesis-related genes(mcrA and rnfC),suggesting a dual mechanism involving direct enzymatic inhibition and microbial community modulation.Conclusions These findings indicate that SAC effectively reduces CH_(4)production by inhibiting MCR activity and reshaping the rumen microbial community.As a plant-derived compound with strong inhibitory effects on methanogenesis,SAC presents a promising and sustainable alternative to synthetic CH_(4) inhibitors,offering potential applications for mitigating CH_(4)emissions in livestock production.展开更多
Methane is considered a potential biosignature gas.The Mars Science Laboratory(MSL)Curiosity rover has observed seasonal variations in atmospheric methane within Gale Crater,suggesting possible microbial activity.The ...Methane is considered a potential biosignature gas.The Mars Science Laboratory(MSL)Curiosity rover has observed seasonal variations in atmospheric methane within Gale Crater,suggesting possible microbial activity.The origin of this methane could be either biological or abiotic or a combination of the two.Different physical mechanisms,involving distinct environmental variables,produce varying concentrations of methane.By analyzing the influence of various environmental variables on methane partial pressures and comparing differences between physical models and empirical measurements,we can better discern methane production mechanisms.This study investigates factors affecting methane cycling.We find that temperature and pressure strongly correlate with Martian atmospheric methane,while Ultraviolet(UV)radiation at the atmospheric boundary and surface UV radiation exhibit weaker correlations.Using Fuller’s method,we successfully reproduce the seasonal methane cycle in Gale Crater.Several potential physical models suggest that gas diffusion driven by variations in pressure and temperature within the shallow subsurface regolith may represent a primary mechanism determining methane concentrations observed in Gale Crater.However,errors in the pressure-dominated model cannot be neglected.As Curiosity enters its uphill exploration phase,we suggest that atmospheric pressure will play a significant role in predicting the methane concentrations that it will detect.展开更多
CO_(2)-free H_(2)refers to H_(2)production process without CO_(2)emission,which is a promising clean energy in the future.Catalytic decomposition of methane(CDM)is a competitive technology to produce CO_(2)-free H2 wi...CO_(2)-free H_(2)refers to H_(2)production process without CO_(2)emission,which is a promising clean energy in the future.Catalytic decomposition of methane(CDM)is a competitive technology to produce CO_(2)-free H2 with large-scale.However,CDM reaction is highly endothermic and is kinetically and thermodynamically unfavorable,which typically requires a harsh reaction temperature above 800℃.In this work,solar-driven photothermal catalytic decomposition of methane was firstly introduced to produce CO_(2)-free H_(2)relying solely on solar energy as the driving force.A high H_(2)yield of 204.6 mmol g^(–1)h^(–1)was observed over Ni-CeO2 interface under photothermal conditions,along with above 87%reduction in the apparent activation energy(11.2 vs.87.3 kJ mol^(–1))when comparing with the traditional thermal catalysis.Further studies suggested that Ni/CeO_(2)catalyst enhanced optical absorption in visible-infrared region to ensure the heat energy for methane decomposition.The generated electrons and holes participated in the redox process of photo-driven CDM reaction with enhanced separation ability of hot carriers excited by ultraviolet-visible light,which lowered activation energy and improved the photothermal catalytic activity.This work provides a promising photothermal catalytic strategy to produce CO_(2)-free H^(2)under mild conditions.展开更多
Because methane is flammable and explosive,the detection process is time-consuming and dangerous,and it is difficult to obtain labeled data.In order to reduce the dependence on marker data when detecting methane conce...Because methane is flammable and explosive,the detection process is time-consuming and dangerous,and it is difficult to obtain labeled data.In order to reduce the dependence on marker data when detecting methane concentration using tunable diode laser absorption spectroscopy(TDLAS)technology,this paper designs a methane gas acquisition platform based on TDLAS and proposes a methane gas concentration detection model based on semi-supervised learning.Firstly,the methane gas is feature extracted,and then semi-supervised learning is introduced to select the optimal feature combination;subsequently,the traditional whale optimization algorithm is improved to optimize the parameters of the random forest to detect the methane gas concentration.The results show that the model is not only able to select the optimal feature combination under limited labeled data,but also has an accuracy of 94.25%,which is better than the traditional model,and is robust in terms of parameter optimization.展开更多
Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions thro...Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions through methanotrophs can provide crucial information for understanding the harsh C-H activation of methane.Soluble methane monooxygenase(sMMO)belongs to the bacterial multi-component monooxygenase superfamily and requires hydroxylase(MMOH),regulatory(MMOB),and reductase(MMOR)components.Recent structural and biophysical studies have demonstrated that these components accelerate and retard methane hydroxylation in MMOH through protein-protein interactions.Complex structures of sMMO,including MMOH-MMOB and MMOH-MMOD,illustrate how these regulatory and inhibitory components orchestrate the di-iron active sites located within the four-helix bundles of MMOH,specifically at the docking surface known as the canyon region.In addition,recent biophysical studies have demonstrated the role of MmoR,aσ54-dependent transcriptional regulator,in regulating sMMO expression.This perspective article introduces remarkable discoveries in recent reports on sMMO components that are crucial for understanding sMMO expression and activities.Our findings provide insight into how sMMO components interact with MMOH to control methane hydroxylation,shedding light on the mechanisms governing sMMO expression and the interactions between activating enzymes and promoters.展开更多
Methane, an abundant one-carbon(C_(1)) resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and ca...Methane, an abundant one-carbon(C_(1)) resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO_(2)emissions and coke deposition. Electrochemical conversion of methane(ECM) using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO_(2)emission.展开更多
Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate c...Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate change on the ecosystem and the rise in methane emissions,it is essential to conduct a bibliometrics study to provide an overview and research trends.We used the Bibliometrix package and VOSviewer to decipher bibliometric indices for methane emissions in cattle farms(MECF).Current dataset were collected from the Web of Science(Core Collection)database,and 8,998 publications were analyzed.The most co-occurring keywords scientists preferred were methane(1,528),greenhouse gas(443),methane emissions(440),and cattle(369).Methane was the most frequently used keyword in the published scientific literature.Thematic evolution of research themes and trend results highlighted carbon dioxide,methane,dairy cattle,cattle,and risk factors during 1999–2017.Chinese Academy of Sciences ranked on top with 485 publications,followed by Agriculture&Agri-Food Canada,University of Colorado,National Oceanic and Atmospheric Administration,and Aarhus University.Chinese Academy of Sciences was also the most cited organization,followed by the University of Colorado,Agriculture&Agri-Food Canada,National Oceanic and Atmospheric Administration,and United States Geological Survey.Source analysis showed that the Science of the Total Environment was cited with the highest total link strength.Science of the Total Environment ranked first in source core 1 with 290 citation frequencies,followed by Journal of Dairy Science with 223 citation frequencies.Currently,no bibliometric study has been conducted on MECF,and to fill this knowledge gap,we carried out this study to highlight methane emissions in cattle farms,aiming at a climate change perspective.In this regard,we focused on the research productivity of countries authors,journals and institutions,co-occurrence of keywords,evolution of research trends,and collaborative networking.Based on relevance degree of centrality,methane emissions and greenhouse gases appeared as basic themes,cattle,and dairy cattle appeared as emerging/declining themes,whereas,methane,greenhouse gas and nitrous oxide appeared to fall amongst basic and motor themes.On the other hand,beef cattle,rumen and dairy cow seem to be between motor and niche themes,and risk factors lie in niche themes.The present bibliometric analysis provides research progress on methane emissions in cattle farms.Current findings may provide a framework for understanding research trends and themes in MECF research.展开更多
Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using se...Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using seaweeds as an anti-methanogenic feed additive has become prevailing in recent years.Asparagopsis taxiformis is the preferred species because it contains a relatively higher concentration of bromoform.As a type of halogenated methane analogue,bromoform contained in A.taxiformis can specifically inhibit the activity of coenzyme M methyltransferase,thereby blocking the ruminal methanogenesis.However,bromoform is a potential toxin and ozone-depleting substance.In response,current research focuses on the effects of bromoform-enriched seaweed supplementation on ruminant productivity and safety,as well as the impact of large-scale cultivation of seaweeds on the atmospheric environment.The current research on seaweed still needs to be improved,especially in developing more species with low bromoform content,such as Bonnemaisonia hamifera,Dictyota bartayresii,and Cystoseira trinodis.Otherwise,seaweed is rich in bioactive substances and exhibits antibacterial,anti-inflammatory,and other physiological properties,but research on the role of these bioactive compounds in methane emissions is lacking.It is worthy of deeper investigation to identify more potential bioactive compounds.As a new focus of attention,seaweed has attracted the interest of many scientists.Nevertheless,seaweed still faces some challenges as a feed additive to ruminants,such as the residues of heavy metals(iodine and bromine)and bromoform in milk or meat,as well as the establishment of a supply chain for seaweed cultivation,preservation,and processing.We have concluded that the methane-reducing efficacy of seaweed is indisputable.However,its application as a commercial feed additive is still influenced by factors such as safety,costs,policy incentives,and regulations.展开更多
Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)format...Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)formation and dissociation are still in controversy.In this study,montmorillonite and illite were separately mixed with quartz sand to investigate their effects on MH formation and dissociation.The microstructure of synthesized samples was observed by cryo-SEM innovatively to understand the effects of montmorillonite and illite on MH phase transition in micron scale.Results show that montmorillonite and illite both show the inhibition on MH formation kinetics and water-to-hydrate conversion,and illite shows a stronger inhibition.The 10 wt%montmorillonite addition significantly retards MH formation rate,and the 20 wt%montmorillonite has a less inhibition on the rate.The increase of illite mass ratio(0-20 wt%)retards the rate of MH formation.As the content of clay minerals increase,the water-to-hydrate conversion decreases.Cryo-SEM images presented that montmorillonite aggregates separate as individual clusters while illite particles pack as face-to-face configuration under the interaction with water.The surface-overlapped illite aggregates would make sediments pack tightly,hinder the contact between gas and water,and result in the more significant inhibition on MH formation kinetics.Under the depressurization method,the addition of clay minerals facilitates MH dissociation rate.Physicochemical properties of clay minerals and MH distribution in the pore space lead to the faster dissociation rate in clay-containing sediments.The results of this study would provide beneficial guides on geological investigations and optimizing strategies of natural gas production in marine hydrate-bearing sediments.展开更多
基金Supported by Innovation Capability Support Program of Shaanxi(2024RS-CXTD-53,2024ZC-KJXX-096)the Key R&D Program of Shaanxi Province(2022QCY-LL-69)Xi’an Science and Technology Project(24GXFW0089)。
文摘Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.
基金Supported by the Science and Technology Major Project of Liaoning Province(2024JH2,1025000892)the Fundamental Research Funds for the Universities of Liaoning Province(LJ232410143051)+1 种基金Liaoning Provincial Science and Technology Program 2023JHl/10400006Shenyang Science and Technology Program(24-213-3-09)。
文摘Methane dehydroaromatization(MDA)presents a promising carbon-neutral pathway for benzene,toluene,and xylene(BTX)production,alternative to petroleumderived routes.Elucidating the regulatory mechanisms of Brønsted acid site(BAS)strength on reaction pathways,alongside the spatial proximity effects between BAS and Mo active sites in bifunctional synergy,remains a critical scientific challenge in catalyst design.This study systematically tunes both BAS strength(via isomorphous metal substitution)and Mo-BAS spatial proximity in zeolites,integrating MDA catalytic evaluations with density functional theory(DFT)calculations to dissect their individual contributions.Strongly acidic BAS catalysts(compared to moderately acidic Fe/Ga-substituted counterparts)exhibit superior performance,evidenced by enhanced aromatic yields.Conversely,weakly acidic Bsubstituted zeolites demonstrate optimal mono-/bifunctional synergy,outperforming moderate-acid systems.DFT results reveal that acid strength dictates C−H activation mechanisms by modulating the energy barriers of rate-determining steps.While Al-zeolites deliver the highest activity,B-substituted systems display unique potential for mechanistic investigations.Spatial proximity analysis indicates that micrometer-scale Mo-BAS distances hinder effective synergy due to exceeding electron interaction and mass transfer limits,whereas nanometer-scale proximity enhances activity(via accelerated intermediate transport)and suppresses coke formation.These findings establish a theoretical framework for rationalizing zeolite catalyst optimization through BAS property engineering and spatial control of Mo-BAS cooperation,providing actionable guidelines for designing next-generation MDA catalysts.
基金Supported by Innovative Research Groups of the National Natural Science Foundation of China(22021004)。
文摘Catalytic decomposition of methane,which produces high-purity hydrogen and high-value-added carbon nanomaterials,has shown considerable potential for development and is expected to yield significant economic benefits in the future.However,designing catalysts that simultaneously exhibit high activity and long-term stability remains a significant challenge.Tuning the catalyst’s structure and electronic properties is an effective strategy for enhancing the reaction performance.In this work,a series of NixZr/ZSM-5 catalysts were prepared using the incipient wetness impregnation method,and the effect of Zr loadings on catalyst properties and performance was systematically investigated.The calcined and reduced catalysts were characterized by low-temperature N_(2)adsorption-desorption,XRD,SEM,H_(2)-TPR and XPS.The results showed that the addition of Zr significantly increased the specific surface area of the catalyst and reduced the metal particle size.Smaller NiO particles were found to enter the pores of the HZSM-5 support,and electronic interactions between NiO and ZrO_(2)markedly enhanced the metal-support interaction.The catalyst exhibited optimal catalytic performance at a Zr loading of 5%,achieving a maximum methane conversion of 68%at 625℃,maintaining activity for 900 min,and delivering a carbon yield of 1927%.Further increasing the Zr loading yielded only limited improvements in catalytic performance.Characterization of the spent catalysts and carbon products via TEM,Raman spectroscopy,and TGA revealed that the introduction of ZrO_(2)reduced metal sintering and promoted a shift in carbon nanofibers growth mode from tip-growth to base-growth.The mechanism of base-growth enabled the catalyst to maintain reaction activity for an extended period.
基金supported by the Cooperative Research Program for Agriculture Science and Technology Development,Republic of Korea(Grant No.RS-2022-RD010034)the 2023 Yellow Sea Wetland International Cooperation Key Project,China(Grant No.HHSDKT202303).
文摘Rice fields are one of the largest sources of methane(CH4),a potent greenhouse gas contributing significantly to global warming.Elucidating the underlying mechanisms and mitigating CH4 emissions from paddy fields is crucial for combating climate change while ensuring sustainable food production.This review investigates the biological processes governing CH4 generation in rice fields,focusing on how soil microorganisms generate CH4 under waterlogged,anaerobic conditions.It also explores the mechanisms by which CH4 escapes into the atmosphere through plant-mediated transport,diffusion,and ebullition.Several factors influencing CH4 emissions are discussed,including soil composition,water management,exogenous organic matter application,rice variety selection,and local climate conditions.Strategies that can be implemented to reduce CH4 emissions are assessed,such as alternate wetting and drying,urea deep placement,biochar application,optimized fertilizer application,and breeding of rice varieties with low CH4 emissions.Novel solutions,such as the enhancement of methane-consuming bacteria in soils using microbial-based approaches,are also explored.The importance of integrating innovative technologies,improved farming practices,and interdisciplinary research is emphasized to develop practical and scalable strategies for reducing CH4 emissions.By addressing these challenges,we can advance towards the attainment of sustainable agriculture and global climate goals.This review aims to serve as a comprehensive resource for researchers,policymakers,and practitioners seeking to understand and mitigate CH4 emissions from rice cultivation.
基金funded by the Beef Cattle Research Council Cluster(FDE.18.21C)Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery,NSERC Canadian Research Chair(Tier 1)program+2 种基金NSERC Alliance program(ALLRP 588541‐23)Foundation for Food&Agriculture Research Greener Cattle Initiative(Award ID 22‐000373)DSM Nutritional Products,Kaiseraugst,Switzerland。
文摘Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen microbiota in beef cattle and how microbes change after 3-NOP withdrawal have not been studied.This study investigated changes in rumen bacteria,archaea,and protozoa after ST and LT dietary supplementation and removal of 3-NOP using metataxonomic analysis.Results A total of 143 rumen samples were collected from two beef cattle studies with 3-NOP supplementation.The ST study(95 samples)used eight ruminally cannulated beef cattle in a 4×4 Latin square design with four 28-d of 3-NOP treatments[mg/kg of dry matter(DM)]:control:0,low:53,med:161,and high:345.The LT study(48 samples)was a completely randomized design with two 3-NOP treatments[control:0,and high:280 mg/kg of DM)fed for 112-d followed by a 16-d withdrawal(without 3-NOP).Bacterial and archaeal communities were significantly affected by 3-NOP supplementation but limited effects on protozoal communities were observed.Under ST supplementation,the relative abundances of Prevotella,Methanobrevibacter(Mbb.)ruminantium,Methanosphaera sp.ISO3-F5,and Entodinium were increased(Q<0.05),whereas those of Mbb.gottschalkii and Epidinium were decreased(Q<0.05)with 3-NOP supplementation.In LT study,relative abundances of Mbb.ruminantium,and Methanosphaera sp.Group5 were increased(Q<0.05),while those of Saccharofermentans and Mbb.gottschalkii were decreased(Q<0.05)with 3-NOP supplementation.Comparison between 3-NOP supplementation and the withdrawal revealed increased relative abundances of Clostridia UCG-014 and Oscillospiraceae NK4A214 group and decreased those of Eubacterium nodatum group and Methanosphaera sp.Group5(P<0.05)after 3-NOP withdrawal.Further comparison of rumen microbiota between control and 3-NOP withdrawal showed significantly higher(P=0.029)relative abundances of Eggerthellaceae DNF00809,p-1088-a5 gut group,and Family XII UCG-001 in control group while no significant differences were detected for archaea and protozoa.Microbial network analysis revealed that microbial interactions differed by both 3-NOP dose and durations.Conclusions Both ST and LT supplementation affected overall rumen microbial profile,with individual microbial groups responded to 3-NOP supplementation differently.After 3-NOP withdrawal,not all microbes showed recovery,indicating that the 3-NOP driven shifts were only partially reversible.These findings provide an understanding of the effects of 3-NOP on rumen microbial communities and their adaptability to methane mitigation strategies.
基金supported by the National Natural Science Foundation of China(No.52500142)the National Postdoctoral Program for Innovative Talents under Grant Number BX20250334the China Postdoctoral Science Foundation(Certificate Number:2025M771285)。
文摘Directly burning methane for energy production wastes chemical potential and exacerbates CO_(2) emissions,while catalytic conversion into high-value fuel/chemicals provides economic and environmental sustainability.Photocatalytic CH_(4) conversion has emerged as a transformative technology,enabling selective oxidation under ambient conditions to directly synthesize value-added organic compounds.This addresses the dual challenges of climate mitigation and sustainable energy conversion.This review systematically examines the development of photocata lytic CH_(4) conversion,with three key dimensions.Firstly,we elucidate fundamental reaction mechanisms governing CH_(4) activation,emphasizing critical steps such as C-H bond scission via charge transfer,intermediate stabilization,and product desorption kinetics.Subsequently,we classify emerging photocata lytic pathways(partial oxidation,coupling,and reforming)and analyze material innovations.Finally,the challenges of the current photocata lytic CH_(4)conversion system and catalyst development were discussed,and perspectives were presented.The overarching objective of this work is to provide a comprehensive roadmap for the development of solardriven CH_(4) conversion systems that are aligned with global carbon neutrality goals.
基金supported by the National Science and Technology Major Project of China(No.2025ZD1405702)the Scientific Research and Technology Development Project of PetroChina Coalbed Methane Co.,Ltd.(Project No.25MQCTSG010)Applied Science and Technology Project of PetroChina Company Limited(2023ZZ18YJ04).
文摘Significant differences exist between deep and medium-shallow coalbed methane(CBM)reservoirs.The unclear understanding of flowback and production behavior severely constrains the development of deep CBM resources.To address this challenge,guided by the gas-liquid two-phase flow theory in ultra-low permeability reservoirs,and integrating theoretical analysis,numerical simulation,and insights from production practices,this study classifies the flowback and production stages of deep CBM well considering the Daning-Jixian Block,Eastern Ordos Basin as a representative case.We summarize the flowback characteristics for each stage and establish a standard flowback production type curve,aiming to guide field operations.The results indicate that:(a)The production process of deep CBM horizontal wells can be divided into five distinct stages:initial single-phase water dewatering stage,initial gas appearance to peak water production stage,gas breakthrough to peak gas production stage,stable production and decline stage,and low-rate production stage.(b)Based on reservoir energy,two standard type curves for horizontal well flowback production are established:the‘Sufficient Reservoir Energy’type and the‘Insufficient Reservoir Energy’type.The former achieves a higher initial gas rate(up to 12×10^(4)m^(3)/d)but exhibits poorer stability,while the latter achieves a lower stable rate(up to 8×10^(4)m^(3)/d)but demonstrates stronger stability.Numerical simulation confirms these behavioral patterns and reveals the underlying mechanisms related to the effectively drained area where pressure is significantly depleted.The findings from this study have guided the flowback production operations in 53 deep CBM wells with positive results,demonstrating high potential for broad application.
基金financial support from the National Key R&D Program of China(2022YFA1504500 and 2023YFA1506300)the National Natural Science Foundation of China(22588201,22225204,and 22472169)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0600100)Liaoning Binhai Laboratory(LBLG-2024-03)。
文摘The traditional ammonia synthesis via the Haber–Bosch process requires large consumption of highpurity H_(2) and causes significant carbon emissions owing to the energy-intensive and complex hydrogen production steps conducted under harsh reaction conditions.Herein,we report a cyclic catalytic process for the production of NH_(3) by directly utilizing earth-abundant CH_(4) as a hydrogen source for N_(2) hydrogenation while simultaneously co-producing H_(2) over an alumina-supported iron catalyst(Fe/Al_(2)O_(3)).It achieves exceptional productivities of 2300μmol g^(-1)h^(-1)for NH_(3) and 400 mmol g^(-1)h^(-1)for H_(2) at700℃.By eliminating the coke that results from CH_(4) pyrolysis through a reaction with the greenhouse gas CO_(2) to produce valuable CO,we establish an atom-economic cyclic catalytic process while producing a CO stream intrinsically separated in the regeneration step.Mechanistic investigations indicate that the iron species in Fe/Al_(2) O_(3) serve as tri-functional active sites for CH_(4) pyrolysis,N_(2) hydrogenation,and coke elimination to produce CO,thus enabling an efficient and environmentally friendly cyclic catalytic process.
基金support from the Zhejiang Provincial Natural Science Foundation of China (No.LQ24B030011)the Ningbo Natural Science Foundation (No.2023J181)+4 种基金the Open Research Fund of Key Laboratory of Functional Inorganic Materials Chemistry of the Ministry of Education (Heilongjiang University)the Start-up Funding offered by Ningbo University of Technology to J.D.LiNational Natural Science Foundation of China (No.U24A2071)Postdoctoral Research Start-up Fund (No.2111224002)Harbin Normal University Talent Plan (No.1305124213) to Y.D.Liu。
文摘The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environmental purification.A major challenge in this field is the chemical inertness of methane and the strong oxidizing nature of photogenerated holes,which can lead to over-oxidation and reduced selectivity and efficiency.To address these issues,we have developed a sodium-doped zinc oxide(Na-ZnO) modified with cobalt oxide(CoO) catalyst.This catalyst has demonstrated excellent performance in converting methane to low alcohols,achieving a yield of 130 μmol g^(-1)h^(-1) and a selectivity of up to 96 %.The doping of Na in ZnO significantly enhances methane adsorption,while the surface-modified CoO effectively captures photogenerated holes,activates water molecules,and uses hydroxyl radicals to activate methane,thus controlling the dehydrogenation degree of methane and preventing the formation of over-oxidized products.This strategy has successfully improved the efficiency and selectivity of photocatalytic methane oxidation to low alcohols,offering a new perspective for the application of photocatalytic technology in energy and environmental fields.
基金supported by the National Key R&D Program of China(2023YFB4104600)National Natural Science Foundation of China(52572313)+1 种基金Tangshan Talent Funding Project(A202202007)Shenzhen Science and Technology Innovation Commission under Grant No.20231120185819001。
文摘Sintering and coking are critical barriers to achieving high performance in dry reforming of methane(DRM)catalysts.A finely dispersed and thermostable Ni-based catalyst is the key to address these issues.By leveraging the intrinsic superiorities of high-entropy oxides in high-temperature stability and low atomic diffusivity,in this study,a highly dispersed Ni-based catalyst is synthesized via an entropycontrolled exsolution of active components.By increasing the number of transition-metal elements in spinel oxides,the active metalsupport interaction(MSI)can be continuously strengthened,which controls the exsolution and thermal stability of Ni-based active metal in harsh reaction conditions of DRM.An optimized medium-entropy spinel(Mg_(0.4)Ni_(0.2)Co_(0.2)Zn_(0.2))Al_(2)O_(4)with the exsolution of finely dispersed Ni–Co nanoparticles displayed superior activity and stability in thermal DRM at 800°C and photothermal DRM.This entropy-controlled MSI and exsolution principle provides a significant strategy for designing robust catalysts resistant to sintering and coking for high-temperature reactions like DRM in thermal and photothermal systems.
基金the financial support from National Natural Science Foundation of China(No.52474029)Strategic and Applied Scientific Research Project of PetroChina Company Limited(2023ZZ18,2023ZZ18YJ04).
文摘In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leading to suboptimal reservoir performance.Currently,there is no well-established method for accurately evaluating the effectiveness of such stimulation.This study introduces,for the first time,the concept of the Fracture Network Bridging Coefficient(FNBC)as a novel metric to assess stimulation performance.By quantitatively coupling the proportions of unstimulated and overstimulated volumes,the FNBC effectively characterizes the connectivity and efficiency of the fracture network.A background grid calibration method is developed to quantify the stage-controlled volume,effectively stimulated volume,unstimulated volume,and repeatedly stimulated volume among different stages of horizontal wells.Furthermore,an optimization model is constructed by taking the FNBC as the objective function and the fracturing injection rate and fluid volume as optimization variables.The Simultaneous Perturbation Stochastic Approximation(SPSA)algorithm is employed to iteratively perturb and optimize these variables,progressively improving the FNBC until the optimal displacement rate and fluid volume corresponding to the maximum FNBC are obtained.Field application in a typical CBM multistage fractured horizontal well in China demonstrates that the FNBC increased from 0.358 to 0.539(a 50.6% improvement),with the injection rate rising from 16 m^(3)/min to 24 m^(3)/min and the average fluid volume per stage increasing from 2490 m^(3) to 3192 m^(3),significantly enhancing the stimulation effectiveness.This research provides theoretical support for designing high-efficiency stimulation strategies in unconventional reservoirs under dynamic limits.
基金funded by the Integrated Demonstration of Scalable and Efficient Healthy Breeding for Cattle and Sheep(Grant No.2022YFD1301100)Instant Intelligent Diagnosis and Risk Warning Methods for Nutritional and Metabolic-Type Periparturient Cow Paralysis(Grant No.2024-YWF-ZYSQ-10)。
文摘Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making it a promising target for CH_(4) mitigation.This study aimed to identify and validate plant-derived inhibitors by using molecular docking to screen compounds with strong binding affinity to the F430 active site of MCR and assessing their efficacy in reducing CH_(4) emissions.Results Molecular docking analysis identified salvianolic acid C(SAC)as a potent inhibitor of MCR,showing a strong binding affinity to the F430 active site(binding energy:-8.2 kcal/mol).Enzymatic inhibition assays confirmed its inhibitory effect,with a half-maximal inhibitory concentration(IC50)of 692.3μmol/L.In vitro rumen fermentation experiments demonstrated that SAC supplementation(1.5 mg/g DM)significantly reduced CH_(4)production(P<0.01)without negatively affecting major fermentation parameters.Microbial community analysis using 16S rRNA sequencing and metagenomics revealed that SAC selectively altered the rumen microbiota,increasing the relative abundance of Bacteroidota while significantly reducing Methanobrevibacter(P=0.04).Moreover,metagenomic analysis showed the downregulation of key methanogenesis-related genes(mcrA and rnfC),suggesting a dual mechanism involving direct enzymatic inhibition and microbial community modulation.Conclusions These findings indicate that SAC effectively reduces CH_(4)production by inhibiting MCR activity and reshaping the rumen microbial community.As a plant-derived compound with strong inhibitory effects on methanogenesis,SAC presents a promising and sustainable alternative to synthetic CH_(4) inhibitors,offering potential applications for mitigating CH_(4)emissions in livestock production.
基金supported by the National Natural Science Foundation of China NSFC(Grant No.42330602,42275139)the National Key Research and Development Program of China(Grant No.2024YFF0809401)+2 种基金the Anhui Provincial Natural Science Foundation(Grant No.2208085UQ02)Innovation Center for Fengyun Meteorological Satellite Special Project(Grant No.FY-APP-ZX-2022.0211)the Joint Laboratory of Fengyun Remote Sensing.
文摘Methane is considered a potential biosignature gas.The Mars Science Laboratory(MSL)Curiosity rover has observed seasonal variations in atmospheric methane within Gale Crater,suggesting possible microbial activity.The origin of this methane could be either biological or abiotic or a combination of the two.Different physical mechanisms,involving distinct environmental variables,produce varying concentrations of methane.By analyzing the influence of various environmental variables on methane partial pressures and comparing differences between physical models and empirical measurements,we can better discern methane production mechanisms.This study investigates factors affecting methane cycling.We find that temperature and pressure strongly correlate with Martian atmospheric methane,while Ultraviolet(UV)radiation at the atmospheric boundary and surface UV radiation exhibit weaker correlations.Using Fuller’s method,we successfully reproduce the seasonal methane cycle in Gale Crater.Several potential physical models suggest that gas diffusion driven by variations in pressure and temperature within the shallow subsurface regolith may represent a primary mechanism determining methane concentrations observed in Gale Crater.However,errors in the pressure-dominated model cannot be neglected.As Curiosity enters its uphill exploration phase,we suggest that atmospheric pressure will play a significant role in predicting the methane concentrations that it will detect.
文摘CO_(2)-free H_(2)refers to H_(2)production process without CO_(2)emission,which is a promising clean energy in the future.Catalytic decomposition of methane(CDM)is a competitive technology to produce CO_(2)-free H2 with large-scale.However,CDM reaction is highly endothermic and is kinetically and thermodynamically unfavorable,which typically requires a harsh reaction temperature above 800℃.In this work,solar-driven photothermal catalytic decomposition of methane was firstly introduced to produce CO_(2)-free H_(2)relying solely on solar energy as the driving force.A high H_(2)yield of 204.6 mmol g^(–1)h^(–1)was observed over Ni-CeO2 interface under photothermal conditions,along with above 87%reduction in the apparent activation energy(11.2 vs.87.3 kJ mol^(–1))when comparing with the traditional thermal catalysis.Further studies suggested that Ni/CeO_(2)catalyst enhanced optical absorption in visible-infrared region to ensure the heat energy for methane decomposition.The generated electrons and holes participated in the redox process of photo-driven CDM reaction with enhanced separation ability of hot carriers excited by ultraviolet-visible light,which lowered activation energy and improved the photothermal catalytic activity.This work provides a promising photothermal catalytic strategy to produce CO_(2)-free H^(2)under mild conditions.
基金supported by the Ministry of Education Chunhui Program of China(No.HZKY20220304).
文摘Because methane is flammable and explosive,the detection process is time-consuming and dangerous,and it is difficult to obtain labeled data.In order to reduce the dependence on marker data when detecting methane concentration using tunable diode laser absorption spectroscopy(TDLAS)technology,this paper designs a methane gas acquisition platform based on TDLAS and proposes a methane gas concentration detection model based on semi-supervised learning.Firstly,the methane gas is feature extracted,and then semi-supervised learning is introduced to select the optimal feature combination;subsequently,the traditional whale optimization algorithm is improved to optimize the parameters of the random forest to detect the methane gas concentration.The results show that the model is not only able to select the optimal feature combination under limited labeled data,but also has an accuracy of 94.25%,which is better than the traditional model,and is robust in terms of parameter optimization.
基金This research was supported by"Regional Innovation Strategy"(2023RIS-008)and"C1 Gas Refinery Program"(NRF-2015M3D3D3A1A01064876)through the National Research Foundation of Koreafunded by the Ministry of Education(NRF-2017R1A6A1A03015876).
文摘Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions through methanotrophs can provide crucial information for understanding the harsh C-H activation of methane.Soluble methane monooxygenase(sMMO)belongs to the bacterial multi-component monooxygenase superfamily and requires hydroxylase(MMOH),regulatory(MMOB),and reductase(MMOR)components.Recent structural and biophysical studies have demonstrated that these components accelerate and retard methane hydroxylation in MMOH through protein-protein interactions.Complex structures of sMMO,including MMOH-MMOB and MMOH-MMOD,illustrate how these regulatory and inhibitory components orchestrate the di-iron active sites located within the four-helix bundles of MMOH,specifically at the docking surface known as the canyon region.In addition,recent biophysical studies have demonstrated the role of MmoR,aσ54-dependent transcriptional regulator,in regulating sMMO expression.This perspective article introduces remarkable discoveries in recent reports on sMMO components that are crucial for understanding sMMO expression and activities.Our findings provide insight into how sMMO components interact with MMOH to control methane hydroxylation,shedding light on the mechanisms governing sMMO expression and the interactions between activating enzymes and promoters.
基金National Key R&D Program of China (2023YFA1508001 and 2023YFA1508002)National Natural Science Foundation of China (22272120 and U2202251)+1 种基金Hainan Province Science and Technology Special Fund(ZDYF2023SHFZ120)Research Foundation of Marine Science and Technology Collaborative Innovation Center of Hainan University (XTCX2022HYB01)。
文摘Methane, an abundant one-carbon(C_(1)) resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO_(2)emissions and coke deposition. Electrochemical conversion of methane(ECM) using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO_(2)emission.
基金supported by the Special Fund for Science and Technology Innovation Strategy of Guangdong Province,China(2022660500250009604)。
文摘Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate change on the ecosystem and the rise in methane emissions,it is essential to conduct a bibliometrics study to provide an overview and research trends.We used the Bibliometrix package and VOSviewer to decipher bibliometric indices for methane emissions in cattle farms(MECF).Current dataset were collected from the Web of Science(Core Collection)database,and 8,998 publications were analyzed.The most co-occurring keywords scientists preferred were methane(1,528),greenhouse gas(443),methane emissions(440),and cattle(369).Methane was the most frequently used keyword in the published scientific literature.Thematic evolution of research themes and trend results highlighted carbon dioxide,methane,dairy cattle,cattle,and risk factors during 1999–2017.Chinese Academy of Sciences ranked on top with 485 publications,followed by Agriculture&Agri-Food Canada,University of Colorado,National Oceanic and Atmospheric Administration,and Aarhus University.Chinese Academy of Sciences was also the most cited organization,followed by the University of Colorado,Agriculture&Agri-Food Canada,National Oceanic and Atmospheric Administration,and United States Geological Survey.Source analysis showed that the Science of the Total Environment was cited with the highest total link strength.Science of the Total Environment ranked first in source core 1 with 290 citation frequencies,followed by Journal of Dairy Science with 223 citation frequencies.Currently,no bibliometric study has been conducted on MECF,and to fill this knowledge gap,we carried out this study to highlight methane emissions in cattle farms,aiming at a climate change perspective.In this regard,we focused on the research productivity of countries authors,journals and institutions,co-occurrence of keywords,evolution of research trends,and collaborative networking.Based on relevance degree of centrality,methane emissions and greenhouse gases appeared as basic themes,cattle,and dairy cattle appeared as emerging/declining themes,whereas,methane,greenhouse gas and nitrous oxide appeared to fall amongst basic and motor themes.On the other hand,beef cattle,rumen and dairy cow seem to be between motor and niche themes,and risk factors lie in niche themes.The present bibliometric analysis provides research progress on methane emissions in cattle farms.Current findings may provide a framework for understanding research trends and themes in MECF research.
基金supported by the Youth Innovation Program of the Chinese Academy of Agricultural Sciences(Y2022QC10)the Agricultural Science and Technology Innovation Program,China(CAAS-ASTIP-2023-IFR-03,CAAS-IFR-ZDRW202302 and CAAS-IFR-ZDRW202404)the Basal Research Fund of the Institute of Feed Research of Chinese Academy of Agricultural Sciences(1610382024009)。
文摘Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using seaweeds as an anti-methanogenic feed additive has become prevailing in recent years.Asparagopsis taxiformis is the preferred species because it contains a relatively higher concentration of bromoform.As a type of halogenated methane analogue,bromoform contained in A.taxiformis can specifically inhibit the activity of coenzyme M methyltransferase,thereby blocking the ruminal methanogenesis.However,bromoform is a potential toxin and ozone-depleting substance.In response,current research focuses on the effects of bromoform-enriched seaweed supplementation on ruminant productivity and safety,as well as the impact of large-scale cultivation of seaweeds on the atmospheric environment.The current research on seaweed still needs to be improved,especially in developing more species with low bromoform content,such as Bonnemaisonia hamifera,Dictyota bartayresii,and Cystoseira trinodis.Otherwise,seaweed is rich in bioactive substances and exhibits antibacterial,anti-inflammatory,and other physiological properties,but research on the role of these bioactive compounds in methane emissions is lacking.It is worthy of deeper investigation to identify more potential bioactive compounds.As a new focus of attention,seaweed has attracted the interest of many scientists.Nevertheless,seaweed still faces some challenges as a feed additive to ruminants,such as the residues of heavy metals(iodine and bromine)and bromoform in milk or meat,as well as the establishment of a supply chain for seaweed cultivation,preservation,and processing.We have concluded that the methane-reducing efficacy of seaweed is indisputable.However,its application as a commercial feed additive is still influenced by factors such as safety,costs,policy incentives,and regulations.
基金supported by the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.IGGCAS-201903).
文摘Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)formation and dissociation are still in controversy.In this study,montmorillonite and illite were separately mixed with quartz sand to investigate their effects on MH formation and dissociation.The microstructure of synthesized samples was observed by cryo-SEM innovatively to understand the effects of montmorillonite and illite on MH phase transition in micron scale.Results show that montmorillonite and illite both show the inhibition on MH formation kinetics and water-to-hydrate conversion,and illite shows a stronger inhibition.The 10 wt%montmorillonite addition significantly retards MH formation rate,and the 20 wt%montmorillonite has a less inhibition on the rate.The increase of illite mass ratio(0-20 wt%)retards the rate of MH formation.As the content of clay minerals increase,the water-to-hydrate conversion decreases.Cryo-SEM images presented that montmorillonite aggregates separate as individual clusters while illite particles pack as face-to-face configuration under the interaction with water.The surface-overlapped illite aggregates would make sediments pack tightly,hinder the contact between gas and water,and result in the more significant inhibition on MH formation kinetics.Under the depressurization method,the addition of clay minerals facilitates MH dissociation rate.Physicochemical properties of clay minerals and MH distribution in the pore space lead to the faster dissociation rate in clay-containing sediments.The results of this study would provide beneficial guides on geological investigations and optimizing strategies of natural gas production in marine hydrate-bearing sediments.
