Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prep...Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prepared,and the influence mechanism of additives on the structure-performance relationship of the catalysts was systematically explored.Through a variety of characterization methods such as XRD,N2 physical adsorption-desorption,TEM,H_(2)-TPR,CO_(2)-TPD and XPS,combined with catalytic performance evaluation experiments,the correlation between the microstructure of catalysts and the reaction performance of CO_(2)hydrogenation to methanol was analyzed in depth.The results show that metal additives significantly improve the performance of catalysts.After the introduction of additives,the specific surface area and pore volume of the catalysts increase,the grain size of Cu decreases,and its dispersion improves.The Ce-modified CZC catalyst exhibited the best performance,with the grain size of CuO as small as 11.41 nm,and the surface oxygen vacancy concentration(OⅡ/OⅠ=3.15)was significantly higher than that of other samples.The reaction performance test shows that under the conditions of 2.8 MPa,8000 h−1 and 280℃,the CO_(2)conversion of the CZC catalyst reached 18.83%,the methanol selectivity was 68.40%,and the methanol yield was 12.88%,all of which are superior to other catalysts.Its excellent performance can be attributed to the fact that CeO_(2)enhances the metal-support interaction,increases the surface basicity,promotes the adsorption and activation of CO_(2),and simultaneously inhibits the reverse water-gas shift side reaction.This study clarifies the structure-activity regulation mechanism of additive modification on Cu-ZnO catalysts,providing a theoretical basis and technical reference for the development of efficient catalysts for CO_(2)hydrogenation to methanol.展开更多
The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the indu...The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the induction period of methanol conversion was shortened by the introduction of long-chain alkanes.However,the addition of long-chain alkanes had little influence on the product distribution.Polymethylbenzenes and the derivatives were the main retained species on spent SSZ-13 catalyst,while adamantanes were the main retained species on SAPO-34.This indicates that coking species formation was mainly related to the further transformation of long-chain alkane/methanol coupling products at acid sites of the molecular sieve.These findings provide valuable information of long chain alkanes conversion and methanol reaction behavior of induction period over small pore CHA molecular sieves.展开更多
Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon...Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon neutrality goals.The hydrogenation of CO_(2)to methanol not only enables carbon sequestration and recycling,but also provides a route to produce high value-added fuels and basic chemical feedstocks,holding significant environmental and economic potential.However,this conversion process is thermodynamically and kinetically limited,and traditional catalyst systems(e.g.,Cu/ZnO/Al_(2)O_(3))exhibit inadequate activity,selectivity,and stability under mild conditions.Therefore,the development of novel high-performance catalysts with precisely tunable structures and functionalities is imperative.Metal-organic frameworks(MOFs),as crystalline porous materials with high surface area,tunable pore structures,and diverse metal-ligand compositions,have the great potential in CO_(2)hydrogenation catalysis.Their structural design flexibility allows for the construction of well-dispersed active sites,tailored electronic environments,and enhanced metal-support interactions.This review systematically summarizes the recent advances in MOF-based and MOF-derived catalysts for CO_(2)hydrogenation to methanol,focusing on four design strategies:(1)spatial confinement and in situ construction,(2)defect engineering and ion-exchange,(3)bimetallic synergy and hybrid structure design,and(4)MOF-derived nanomaterial synthesis.These approaches significantly improve CO_(2)conversion and methanol selectivity by optimizing metal dispersion,interfacial structures,and reaction pathways.The reaction mechanism is further explored by focusing on the three main reaction pathways:the formate pathway(HCOO*),the RWGS(Reverse Water Gas Shift reaction)+CO*hydrogenation pathway,and the trans-COOH pathway.In situ spectroscopic studies and density functional theory(DFT)calculations elucidate the formation and transformation of key intermediates,as well as the roles of active sites,metal-support interfaces,oxygen vacancies,and promoters.Additionally,representative catalytic performance data for MOFbased systems are compiled and compared,demonstrating their advantages over traditional catalysts in terms of CO_(2)conversion,methanol selectivity,and space-time yield.Future perspectives for MOF-based CO_(2)hydrogenation catalysts will prioritize two main directions:structural design and mechanistic understanding.The precise construction of active sites through multi-metallic synergy,defect engineering,and interfacial electronic modulation should be made to enhance catalyst selectivity and stability.In addition,advanced in situ characterization techniques combined with theoretical modeling are essential to unravel the detailed reaction mechanisms and intermediate behaviors,thereby guiding rational catalyst design.Moreover,to enable industrial application,challenges related to thermal/hydrothermal stability,catalyst recyclability,and cost-effective large-scale synthesis must be addressed.The development of green,scalable preparation methods and the integration of MOF catalysts into practical reaction systems(e.g.,flow reactors)will be crucial for bridging the gap between laboratory research and commercial deployment.Ultimately,multi-scale structure-performance optimization and catalytic system integration will be vital for accelerating the industrialization of MOF-based CO_(2)-to-methanol technologies.展开更多
Converting CO_(2)with green hydrogen to methanol as a carbon-neutral liquid fuel is a promising route for the long-term storage and distribution of intermittent renewable energy.Nevertheless,attaining highly efficient...Converting CO_(2)with green hydrogen to methanol as a carbon-neutral liquid fuel is a promising route for the long-term storage and distribution of intermittent renewable energy.Nevertheless,attaining highly efficient methanol synthesis catalysts from the vast composition space remains a significant challenge.Here we present a machine learning framework for accelerating the development of high space-time yield(STY)methanol synthesis catalysts.A database of methanol synthesis catalysts has been compiled,consisting of catalyst composition,preparation parameters,structural characteristics,reaction conditions and their corresponding catalytic performance.A methodology for constructing catalyst features based on the intrinsic physicochemical properties of the catalyst components has been developed,which significantly reduced the data dimensionality and enhanced the efficiency of machine learning operations.Two high-precision machine learning prediction models for the activities and product selectivity of catalysts were trained and obtained.Using this machine learning framework,an efficient search was achieved within the catalyst composition space,leading to the successful identification of high STY multielement oxide methanol synthesis catalysts.Notably,the CuZnAlTi catalyst achieved high STYs of 0.49 and 0.65 g_(MeOH)/(g_(catalyst)h)for CO_(2)and CO hydrogenation to methanol at 250℃,respectively,and the STY was further increased to 2.63 g_(Me OH)/(g_(catalyst)h)in CO and CO_(2)co-hydrogenation.展开更多
Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride he...Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures(denoted PtPdAu/BiTe)were synthesized using a visible-light-assisted strategy.The coupling alloy and interfacial effects of PtPdAu/BiTe significantly improved the performance and stability of both the ethanol oxidation reaction(EOR)and methanol oxidation reaction(MOR).Introducing a small amount of Au effectively enhanced the CO tolerance of PtPdAu/BiTe compared to dendritic platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures.PtPdAu/BiTe exhibited mass activities of 31.5 and 13.3 A·mg_(Pt)^(-1)in EOR and MOR,respectively,which were 34.4 and 13.2 times higher than those of commercial Pt black,revealing efficient Pt atom utilization.In-situ Fourier transform infrared spectroscopy demonstrated complete 12e^(-)and 6e^(-)oxidation of ethanol and methanol on PtPdAu/BiTe.The PtPdAu/BiTe/C achieved mass peak power densities of 131 and 156 mW·mg_(Pt)^(-1),which were 2.4 and 2.2 times higher than those of Pt/C in practical direct ethanol fuel cell(DEFC)and direct methanol fuel cell(DMFC),respectively,highlighting their potential application in DEFC and DMFC.This study introduces an effective strategy for designing efficient and highly CO tolerant anodic electrocatalysts for practical DEFC and DMFC applications.展开更多
Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density...Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density functional theory(DFT)calculations were performed at first to study the d–d orbital interaction of metallic Pt Pd Cu,revealing that the incorporation of Pd and Cu atoms into Pt system can enhance d-d electron interaction via capturing antibonding orbital electrons of Pt to fill the surrounding Pd and Cu atoms.Under the theoretical guidance,Pt Pd Cu medium entropy alloy aerogels(Pt Pd Cu MEAAs)catalysts have been designed and systematically screened for MOR under acid,alkaline and neutral electrolyte.Furthermore,DFT calculation and in-situ fourier transform infrared spectroscopy analysis indicate that Pt Pd Cu MEAAs follow the direct pathway via formate as the reactive intermediate to be directly oxidized to CO_(2).For practical direct methanol fuel cells(DMFCs),the Pt Pd Cu MEAAs-integrated ultra-thin catalyst layer(4–5μm thickness)as anode exhibits higher peak power density of 35 m W/cm^(2) than commercial Pt/C of 20 m W/cm^(2)(~40μm thickness)under the similar noble metal loading and an impressive stability retention at a 50-m A/cm^(2) constant current for 10 h.This work clearly proves that optimizing the intermediate adsorption capacity via d-d orbital coupling is an effective strategy to design highly efficient catalysts for DMFCs.展开更多
The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation...The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.展开更多
China has abundant renewable energy resources.With the establishment of carbon peaking and carbon neutrality goals,renewable energy sources such as wind power and photovoltaics have undergone tremendous development.Ho...China has abundant renewable energy resources.With the establishment of carbon peaking and carbon neutrality goals,renewable energy sources such as wind power and photovoltaics have undergone tremendous development.However,because of the randomness and volatility of wind and photovoltaic power,the large-scale development of renewable energy faces challenges with accommodation and transmission.At present,the bundling of wind–photovoltaic–thermal power with ultra-high voltage transmission projects is the main development approach for renewable energy bases in western and northern China.Nonetheless,solving the problems of high carbon dioxide emission,carbon dioxide capture,and the utilization of thermal power is still necessary.Based on power-to-hydrogen,powerto-methanol,and oxygen-enriched combustion power generation technologies,this article proposes a power-to-hydrogen-andmethanol model based on the collaborative optimization of energy flow and material flow,which is expected to simultaneously solve the problems of renewable energy accommodation and low-carbon transformation of thermal power.Models with different ways of linking power to hydrogen and methanol are established,and an 8760-hour-time-series operation simulation is incorporated into the planning model.A case study is then conducted on renewable energy bases in the deserts of western and northern China.The results show that the power-to-hydrogen-and-methanol model based on the collaborative optimization of energy flow and material flow can greatly reduce the demand for hydrogen storage and energy storage,reduce the cost of carbon capture,make full use of by-product oxygen and captured carbon dioxide,and produce high-value chemical raw materials,thus exhibiting significant economic advantages.展开更多
The production of renewable methanol(CH_(3)OH)via the photocatalytic hydrogenation of CO_(2) is an ideal method to ameliorate energy shortages and mitigate CO_(2) emissions:however,the highly selective synthesis of me...The production of renewable methanol(CH_(3)OH)via the photocatalytic hydrogenation of CO_(2) is an ideal method to ameliorate energy shortages and mitigate CO_(2) emissions:however,the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift(RWGS)reaction.Herein,we present a novel approach for the synthesis of CH_(3)OH via photocatalytic CO_(2) hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy(OV)-rich molybdenum dioxide(MoO_(2)),resulting in a remarkable selectivity of 43.78%.The active sites in the Au/MoO_(2) catalyst are high-density Au-oxygen vacancies,which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation.This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO_(2) to CH_(3)OH.展开更多
As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol syn...As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.展开更多
Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active...Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.展开更多
The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synt...The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synthesis technique is reported to fabricate atom-nanoisland-sea structured SACs for the first time.The resultant catalysts are constructed by Pt single atoms on In_(2)O_(3)supported by Co3O4nanoislands uniformly dispersed in the sea of reduced graphene oxide.The laser process,with a maximum temperature of 2349 K within~100μs,produced abundant oxygen vacancies(up to 70.8%)and strong interactions between the Pt single atoms and In_(2)O_(3).The laser-synthesized catalysts exhibited a remarkable catalytic performance towards CO_(2)hydrogenation to methanol at 300°C with a CO_(2)conversion of 30.3%,methanol selectivity of 90.6%and exceptional stability over 48 h without any deactivation,outperforming most of the relevant catalysts reported in the literature.Characterization of the spent catalysts after testing for 48 h reveals that the Pt single atoms were retained and the oxygen vacancies remained almost unchanged.In situ diffuse reflectance infrared Fourier transform spectrum was conducted to establish the reaction mechanism supported by the density functional theory simulations.It is believed that this laser synthesis strategy opens a new avenue towards rapidly manufacturing highly active and robust thermal SACs.展开更多
This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefie...This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.展开更多
The excellent catalysts for anodic methanol oxidation reaction(MOR)of direct methanol fuel cells(DMFCs)require a weaker*CO adsorption but a stronger*OH adsorption.Nevertheless,the adsorption strength of the benchmark ...The excellent catalysts for anodic methanol oxidation reaction(MOR)of direct methanol fuel cells(DMFCs)require a weaker*CO adsorption but a stronger*OH adsorption.Nevertheless,the adsorption strength of the benchmark Pt-based electrocatalysts to the oxygen-containing species is generally a scaling relationship.To solve this problem,a stable Pt_(3)Sn_(0.7)Cr_(0.3)intermetallic structure with appropriate adsorption energies of dualintermediates is designed and achieved.Both experimental and density functional theory calculations corroborate that the addition of Cr brought more electron transfer and stronger orbital hybridization,which upgrades the electron density of Pt but reversely downgrades that of Sn.Consequently,the adsorption site of*OH as well as the adsorption energies of*CO and*OH on Pt_(3)Sn_(0.7)Cr_(0.3)surface were optimized at the same time.Beyond providing a promising DMFC electrocatalyst that breaks the scaling adsorption relationship of oxygen-containing species,this work presents valuable insights into the atomic-level rational design of catalysts according to the reaction mechanism.展开更多
The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,...The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,Pd and Ru) modified Cu/alkalized sepiolite(CuX/SEPA) catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures.The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g^(-1)·h^(-1) and methanol selectivity of 90% under the optimal reaction conditions.Various characterizations demonstrated that the addition of Ru promoted the formation of Cu^(2+)and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs,which facilitated the formation of reactive dicopper species([Cu_(2)O]^(2+)or [Cu_(2)O_(2)]^(2+)).Investigation of the reaction mechanism revealed that [Cu_(2)O]^(2+) or [Cu_(2)O_(2)]^(2+) species could adsorb and activate methane to form CH_(3)O^(*) species and ultimately generated methanol with the assistance of water.展开更多
Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains ...Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains challenging,inhibiting the rational design of excellent FeV-based catalysts.Here,in this work,a series of FeV catalysts with various compositions,including FeVO_(4),isolated VO_(x),low-polymerized V_(n)O_(x),and crystalline V_(2)O_(5) were prepared by controlling the preparation conditions,and were applied to methanol oxidation to formaldehyde reaction.A FeV_(1.1) catalyst,which consisted of FeVO_(4) and low-polymerized V_(n)O_(x) species showed an excellent catalytic performance with a methanol conversion of 92.3%and a formaldehyde selectivity of 90.6%,which was comparable to that of conventional iron-molybdate catalyst.The results of CH_(3)OH-IR,O_(2) pulse and control experiments revealed a crucial synergistic effect between FeVO_(4) and low-polymerized V_(n)O_(x).It enhanced the oxygen supply capacity and suitable binding and adsorption strengths for formaldehyde intermediates,contributing to the high catalytic activity and formaldehyde selectivity.This study not only advances the understanding of FeV structure but also offers valuable guidelines for selective methanol oxidation to formaldehyde.展开更多
CuZn-based catalyst is an attractive catalyst for methanol synthesis from CO_(2)hydrogenation,but it early deactivates and its methanol yield still needs to improve.In this study,Y_(2)O_(3)was introduced to Cu/ZnO usi...CuZn-based catalyst is an attractive catalyst for methanol synthesis from CO_(2)hydrogenation,but it early deactivates and its methanol yield still needs to improve.In this study,Y_(2)O_(3)was introduced to Cu/ZnO using a one-pot hydrothermal method,and exhibits a synergistic effect of ZnO and Y_(2)O_(3)on enhancing methanol yield and the stability.We found that the interaction between Y_(2)O_(3)and ZnO results in abundant oxygen vacancies formation,thereby enhancing CO_(2)adsorption and activation.Kinetic analysis and in situ DRIFTS suggest that RWGS forming CO and methanol formation compete for a mutual intermediate HCOO^(*),and the introduction of Y_(2)O_(3)to Cu/ZnO raises the energy barrier for the CO formation but lowers that for methanol formation,thus enhancing the methanol yield on Cu/ZnO/Y_(2)O_(3).展开更多
Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst m...Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.展开更多
The electrochemical conversion of carbon dioxide into valuable products is pivotal for maintaining the global carbon cycle and mitigating global warming.This review explores the advancements in electrochemical CO_(2) ...The electrochemical conversion of carbon dioxide into valuable products is pivotal for maintaining the global carbon cycle and mitigating global warming.This review explores the advancements in electrochemical CO_(2) conversion,particularly focusing on producing methanol,ethanol,and n-propanol using various catalysts such as metals,metal oxides,metal alloys,and metal organic frameworks.Additionally,it covers the photoelectrochemical(PEC)conversion of CO_(2) into alcohols.The primary objective is to identify efficient electrocatalysts for ethanol,methanol,and n-propanol production,prioritizing selectivity,stability,Faradaic efficiency(FE),and current density.Notable catalysts include PtxZn nanoalloys,which exhibit an FE of~81.4% for methanol production,and trimetallic Pt/Pb/Zn nanoalloys,aimed at reducing Pt costs while enhancing catalyst stability and durability.Metal oxide catalysts like thin film Cu_(2)O/CuO on nickel foam and Cu_(2)O/ZnO achieve FE values of~38% and~16.6% for methanol production,respectively.Copper-based metal-organic frameworks,such as Cu@Cu_(2)O,demonstrate an FE of~45% for methanol production.Similarly,Ag_(0.14)/Cu_(0.86) and Cu-Zn alloys exhibit FEs of~63% and~46.6%,respectively,for ethanol production.Notably,n-propanol production via Pd–Cu alloy and graphene/ZnO/Cu_(2)O yields FEs of~13.7% and~23%,respectively.Furthermore,the review discusses recent advancements in PEC reactor design,photoelectrodes,reaction mechanisms,and catalyst durability.By evaluating the efficiency of these devices in liquid fuel production,the review addresses challenges and prospects in CO_(2) conversion for obtaining various valuable products.展开更多
Single carbon products(C1 compounds) are simple but important chemicals in the road towards energy transition.Catalytic conversion of CO_(2) with H_(2)(desirably renewable) can be performed over reducible oxides suppo...Single carbon products(C1 compounds) are simple but important chemicals in the road towards energy transition.Catalytic conversion of CO_(2) with H_(2)(desirably renewable) can be performed over reducible oxides supporting transition metals to obtain products such as CH_(4),CO and MeOH.Oxygen vacancies(O-vacancies),which are inherent defects of reducible metal oxides,play an enormous role in driving the catalytic performance(activity,selectivity,stability) for the desired reactions.Yet,the assessment of O-defects at realistic conditions is often complex.Only few techniques can provide direct evidence for their existence and influence in CO_(2) activation.Among them,electron paramagnetic spectroscopy(EPR),Raman spectroscopy,scanning probe microscopies(SPM) and environmental transmission electron microscopy(ETEM) are nowadays the most informative.In most cases,however,the measurements require reaction conditions far away from CO_(2) valorization applications.Although great efforts have been fruitful in explaining and demonstrating the huge importance of O-vacancies in CO_(2) catalysis,still ambiguous or erroneous interpretations about structure-function correlations involving O-vacancies are found in literature,especially,when information is not properly gathered,e.g.,by O 1s ex-situ X-ray photon spectroscopy(XPS).Moreover,despite the recognized importance of O-vacancies for CO_(2) valorization,critical literature compilations about their effects in thermal processes are scarce.Herein,we attempt to contribute in closing this gap by integrally encompassing representative investigations on the thermo-catalytic production of CH_(4),CO and MeOH.Particularly,we emphasize on the proper selection of assessment tools(direct/indirect) to unambiguously establish structure-function relationships to design optimized O-defective catalysts for the targeted compounds.展开更多
基金Supported by National Key R&D Program of China(2022YFA1503400)。
文摘Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prepared,and the influence mechanism of additives on the structure-performance relationship of the catalysts was systematically explored.Through a variety of characterization methods such as XRD,N2 physical adsorption-desorption,TEM,H_(2)-TPR,CO_(2)-TPD and XPS,combined with catalytic performance evaluation experiments,the correlation between the microstructure of catalysts and the reaction performance of CO_(2)hydrogenation to methanol was analyzed in depth.The results show that metal additives significantly improve the performance of catalysts.After the introduction of additives,the specific surface area and pore volume of the catalysts increase,the grain size of Cu decreases,and its dispersion improves.The Ce-modified CZC catalyst exhibited the best performance,with the grain size of CuO as small as 11.41 nm,and the surface oxygen vacancy concentration(OⅡ/OⅠ=3.15)was significantly higher than that of other samples.The reaction performance test shows that under the conditions of 2.8 MPa,8000 h−1 and 280℃,the CO_(2)conversion of the CZC catalyst reached 18.83%,the methanol selectivity was 68.40%,and the methanol yield was 12.88%,all of which are superior to other catalysts.Its excellent performance can be attributed to the fact that CeO_(2)enhances the metal-support interaction,increases the surface basicity,promotes the adsorption and activation of CO_(2),and simultaneously inhibits the reverse water-gas shift side reaction.This study clarifies the structure-activity regulation mechanism of additive modification on Cu-ZnO catalysts,providing a theoretical basis and technical reference for the development of efficient catalysts for CO_(2)hydrogenation to methanol.
基金Supported by National Natural Science Foundation of China(21991093)。
文摘The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the induction period of methanol conversion was shortened by the introduction of long-chain alkanes.However,the addition of long-chain alkanes had little influence on the product distribution.Polymethylbenzenes and the derivatives were the main retained species on spent SSZ-13 catalyst,while adamantanes were the main retained species on SAPO-34.This indicates that coking species formation was mainly related to the further transformation of long-chain alkane/methanol coupling products at acid sites of the molecular sieve.These findings provide valuable information of long chain alkanes conversion and methanol reaction behavior of induction period over small pore CHA molecular sieves.
基金Supported by the National Key Research and Development Program of China(2023YFB4104500,2023YFB4104502)the National Natural Science Foundation of China(22138013)the Taishan Scholar Project(ts201712020).
文摘Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon neutrality goals.The hydrogenation of CO_(2)to methanol not only enables carbon sequestration and recycling,but also provides a route to produce high value-added fuels and basic chemical feedstocks,holding significant environmental and economic potential.However,this conversion process is thermodynamically and kinetically limited,and traditional catalyst systems(e.g.,Cu/ZnO/Al_(2)O_(3))exhibit inadequate activity,selectivity,and stability under mild conditions.Therefore,the development of novel high-performance catalysts with precisely tunable structures and functionalities is imperative.Metal-organic frameworks(MOFs),as crystalline porous materials with high surface area,tunable pore structures,and diverse metal-ligand compositions,have the great potential in CO_(2)hydrogenation catalysis.Their structural design flexibility allows for the construction of well-dispersed active sites,tailored electronic environments,and enhanced metal-support interactions.This review systematically summarizes the recent advances in MOF-based and MOF-derived catalysts for CO_(2)hydrogenation to methanol,focusing on four design strategies:(1)spatial confinement and in situ construction,(2)defect engineering and ion-exchange,(3)bimetallic synergy and hybrid structure design,and(4)MOF-derived nanomaterial synthesis.These approaches significantly improve CO_(2)conversion and methanol selectivity by optimizing metal dispersion,interfacial structures,and reaction pathways.The reaction mechanism is further explored by focusing on the three main reaction pathways:the formate pathway(HCOO*),the RWGS(Reverse Water Gas Shift reaction)+CO*hydrogenation pathway,and the trans-COOH pathway.In situ spectroscopic studies and density functional theory(DFT)calculations elucidate the formation and transformation of key intermediates,as well as the roles of active sites,metal-support interfaces,oxygen vacancies,and promoters.Additionally,representative catalytic performance data for MOFbased systems are compiled and compared,demonstrating their advantages over traditional catalysts in terms of CO_(2)conversion,methanol selectivity,and space-time yield.Future perspectives for MOF-based CO_(2)hydrogenation catalysts will prioritize two main directions:structural design and mechanistic understanding.The precise construction of active sites through multi-metallic synergy,defect engineering,and interfacial electronic modulation should be made to enhance catalyst selectivity and stability.In addition,advanced in situ characterization techniques combined with theoretical modeling are essential to unravel the detailed reaction mechanisms and intermediate behaviors,thereby guiding rational catalyst design.Moreover,to enable industrial application,challenges related to thermal/hydrothermal stability,catalyst recyclability,and cost-effective large-scale synthesis must be addressed.The development of green,scalable preparation methods and the integration of MOF catalysts into practical reaction systems(e.g.,flow reactors)will be crucial for bridging the gap between laboratory research and commercial deployment.Ultimately,multi-scale structure-performance optimization and catalytic system integration will be vital for accelerating the industrialization of MOF-based CO_(2)-to-methanol technologies.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LDT23E06012E06)National Key R&D Program of China(2023YFC3710800)+3 种基金the National EnergySaving and Low-Carbon Materials Production and Application Demonstration Platform Program(TC220H06N)Pioneer R&D Program of Zhejiang Province-China(2024SSYS0066,2023C03016)National Natural Science Foundation of China(42341208)Zhejiang Energy Group Research Fund(ZNKJ-2023-100)。
文摘Converting CO_(2)with green hydrogen to methanol as a carbon-neutral liquid fuel is a promising route for the long-term storage and distribution of intermittent renewable energy.Nevertheless,attaining highly efficient methanol synthesis catalysts from the vast composition space remains a significant challenge.Here we present a machine learning framework for accelerating the development of high space-time yield(STY)methanol synthesis catalysts.A database of methanol synthesis catalysts has been compiled,consisting of catalyst composition,preparation parameters,structural characteristics,reaction conditions and their corresponding catalytic performance.A methodology for constructing catalyst features based on the intrinsic physicochemical properties of the catalyst components has been developed,which significantly reduced the data dimensionality and enhanced the efficiency of machine learning operations.Two high-precision machine learning prediction models for the activities and product selectivity of catalysts were trained and obtained.Using this machine learning framework,an efficient search was achieved within the catalyst composition space,leading to the successful identification of high STY multielement oxide methanol synthesis catalysts.Notably,the CuZnAlTi catalyst achieved high STYs of 0.49 and 0.65 g_(MeOH)/(g_(catalyst)h)for CO_(2)and CO hydrogenation to methanol at 250℃,respectively,and the STY was further increased to 2.63 g_(Me OH)/(g_(catalyst)h)in CO and CO_(2)co-hydrogenation.
基金supported by the National Natural Science Foundation of China(No.22465009)the Education Department of Guizhou Province(No.2021312)the Foundation of Guizhou Province(No.2019-5666).
文摘Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures(denoted PtPdAu/BiTe)were synthesized using a visible-light-assisted strategy.The coupling alloy and interfacial effects of PtPdAu/BiTe significantly improved the performance and stability of both the ethanol oxidation reaction(EOR)and methanol oxidation reaction(MOR).Introducing a small amount of Au effectively enhanced the CO tolerance of PtPdAu/BiTe compared to dendritic platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures.PtPdAu/BiTe exhibited mass activities of 31.5 and 13.3 A·mg_(Pt)^(-1)in EOR and MOR,respectively,which were 34.4 and 13.2 times higher than those of commercial Pt black,revealing efficient Pt atom utilization.In-situ Fourier transform infrared spectroscopy demonstrated complete 12e^(-)and 6e^(-)oxidation of ethanol and methanol on PtPdAu/BiTe.The PtPdAu/BiTe/C achieved mass peak power densities of 131 and 156 mW·mg_(Pt)^(-1),which were 2.4 and 2.2 times higher than those of Pt/C in practical direct ethanol fuel cell(DEFC)and direct methanol fuel cell(DMFC),respectively,highlighting their potential application in DEFC and DMFC.This study introduces an effective strategy for designing efficient and highly CO tolerant anodic electrocatalysts for practical DEFC and DMFC applications.
基金financially supported by the National Natural Science Foundation of China(Nos.52073214 and 22075211)Guangxi Natural Science Fund for Distinguished Young Scholars(No.2024GXNSFFA010008)+5 种基金Natural Science Foundation of Shandong Province(Nos.ZR2023MB049 and ZR2021QB129)China Postdoctoral Science Foundation(No.2020M670483)Science Foundation of Weifang University(No.2023BS11)supported by the open research fund of the Laboratory of Xinjiang Native Medicinal and Edible Plant Resources Chemistry at Kashi Universitysupported by the Tianhe Qingsuo Open Research Fund of TSYS in 2022 and NSCC-TJNankai University Large-scale Instrument Experimental Technology R&D Project(No.21NKSYJS09)。
文摘Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density functional theory(DFT)calculations were performed at first to study the d–d orbital interaction of metallic Pt Pd Cu,revealing that the incorporation of Pd and Cu atoms into Pt system can enhance d-d electron interaction via capturing antibonding orbital electrons of Pt to fill the surrounding Pd and Cu atoms.Under the theoretical guidance,Pt Pd Cu medium entropy alloy aerogels(Pt Pd Cu MEAAs)catalysts have been designed and systematically screened for MOR under acid,alkaline and neutral electrolyte.Furthermore,DFT calculation and in-situ fourier transform infrared spectroscopy analysis indicate that Pt Pd Cu MEAAs follow the direct pathway via formate as the reactive intermediate to be directly oxidized to CO_(2).For practical direct methanol fuel cells(DMFCs),the Pt Pd Cu MEAAs-integrated ultra-thin catalyst layer(4–5μm thickness)as anode exhibits higher peak power density of 35 m W/cm^(2) than commercial Pt/C of 20 m W/cm^(2)(~40μm thickness)under the similar noble metal loading and an impressive stability retention at a 50-m A/cm^(2) constant current for 10 h.This work clearly proves that optimizing the intermediate adsorption capacity via d-d orbital coupling is an effective strategy to design highly efficient catalysts for DMFCs.
基金the Canadian NRCan OERD Energy Innovation Programthe Natural Sciences and Engineering Research Council of Canada,and the Carbon Solution Program for their financial support.
文摘The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.
基金the financial support provided by the Major Program of Xiangjiang Laboratory(No.23XJ01006).
文摘China has abundant renewable energy resources.With the establishment of carbon peaking and carbon neutrality goals,renewable energy sources such as wind power and photovoltaics have undergone tremendous development.However,because of the randomness and volatility of wind and photovoltaic power,the large-scale development of renewable energy faces challenges with accommodation and transmission.At present,the bundling of wind–photovoltaic–thermal power with ultra-high voltage transmission projects is the main development approach for renewable energy bases in western and northern China.Nonetheless,solving the problems of high carbon dioxide emission,carbon dioxide capture,and the utilization of thermal power is still necessary.Based on power-to-hydrogen,powerto-methanol,and oxygen-enriched combustion power generation technologies,this article proposes a power-to-hydrogen-andmethanol model based on the collaborative optimization of energy flow and material flow,which is expected to simultaneously solve the problems of renewable energy accommodation and low-carbon transformation of thermal power.Models with different ways of linking power to hydrogen and methanol are established,and an 8760-hour-time-series operation simulation is incorporated into the planning model.A case study is then conducted on renewable energy bases in the deserts of western and northern China.The results show that the power-to-hydrogen-and-methanol model based on the collaborative optimization of energy flow and material flow can greatly reduce the demand for hydrogen storage and energy storage,reduce the cost of carbon capture,make full use of by-product oxygen and captured carbon dioxide,and produce high-value chemical raw materials,thus exhibiting significant economic advantages.
文摘The production of renewable methanol(CH_(3)OH)via the photocatalytic hydrogenation of CO_(2) is an ideal method to ameliorate energy shortages and mitigate CO_(2) emissions:however,the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift(RWGS)reaction.Herein,we present a novel approach for the synthesis of CH_(3)OH via photocatalytic CO_(2) hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy(OV)-rich molybdenum dioxide(MoO_(2)),resulting in a remarkable selectivity of 43.78%.The active sites in the Au/MoO_(2) catalyst are high-density Au-oxygen vacancies,which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation.This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO_(2) to CH_(3)OH.
文摘As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.
基金supported by Research Grant from China Petroleum and Chemical Corp。
文摘Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.
基金supported by the Ningbo Yongjiang Science and Technology Programme(2023A-161-C)。
文摘The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synthesis technique is reported to fabricate atom-nanoisland-sea structured SACs for the first time.The resultant catalysts are constructed by Pt single atoms on In_(2)O_(3)supported by Co3O4nanoislands uniformly dispersed in the sea of reduced graphene oxide.The laser process,with a maximum temperature of 2349 K within~100μs,produced abundant oxygen vacancies(up to 70.8%)and strong interactions between the Pt single atoms and In_(2)O_(3).The laser-synthesized catalysts exhibited a remarkable catalytic performance towards CO_(2)hydrogenation to methanol at 300°C with a CO_(2)conversion of 30.3%,methanol selectivity of 90.6%and exceptional stability over 48 h without any deactivation,outperforming most of the relevant catalysts reported in the literature.Characterization of the spent catalysts after testing for 48 h reveals that the Pt single atoms were retained and the oxygen vacancies remained almost unchanged.In situ diffuse reflectance infrared Fourier transform spectrum was conducted to establish the reaction mechanism supported by the density functional theory simulations.It is believed that this laser synthesis strategy opens a new avenue towards rapidly manufacturing highly active and robust thermal SACs.
文摘This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.
基金supported by the Guizhou Provincial Basic Research Program(Natural Science)(No.QianKeHeJiChu ZK[2024]YiBan008)the Special Fund for Natural Science of Guizhou University(Nos.202134,202133)the 2023 Open Fund of Guangdong Provincial Key Laboratory of Fuel Cell Technology(No.FC202321)。
文摘The excellent catalysts for anodic methanol oxidation reaction(MOR)of direct methanol fuel cells(DMFCs)require a weaker*CO adsorption but a stronger*OH adsorption.Nevertheless,the adsorption strength of the benchmark Pt-based electrocatalysts to the oxygen-containing species is generally a scaling relationship.To solve this problem,a stable Pt_(3)Sn_(0.7)Cr_(0.3)intermetallic structure with appropriate adsorption energies of dualintermediates is designed and achieved.Both experimental and density functional theory calculations corroborate that the addition of Cr brought more electron transfer and stronger orbital hybridization,which upgrades the electron density of Pt but reversely downgrades that of Sn.Consequently,the adsorption site of*OH as well as the adsorption energies of*CO and*OH on Pt_(3)Sn_(0.7)Cr_(0.3)surface were optimized at the same time.Beyond providing a promising DMFC electrocatalyst that breaks the scaling adsorption relationship of oxygen-containing species,this work presents valuable insights into the atomic-level rational design of catalysts according to the reaction mechanism.
基金financial assistance from the Anhui Provincial Major Science and Technology Project(202003a05020022)the Institute of Energy,Hefei Comprehensive National Science Center(21KZS219)。
文摘The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,Pd and Ru) modified Cu/alkalized sepiolite(CuX/SEPA) catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures.The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g^(-1)·h^(-1) and methanol selectivity of 90% under the optimal reaction conditions.Various characterizations demonstrated that the addition of Ru promoted the formation of Cu^(2+)and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs,which facilitated the formation of reactive dicopper species([Cu_(2)O]^(2+)or [Cu_(2)O_(2)]^(2+)).Investigation of the reaction mechanism revealed that [Cu_(2)O]^(2+) or [Cu_(2)O_(2)]^(2+) species could adsorb and activate methane to form CH_(3)O^(*) species and ultimately generated methanol with the assistance of water.
文摘Iron-Vanadium(FeV)catalyst showed a unique catalytic activity for the selective oxidation of methanol to formaldehyde;however,due to its complex compositions,the identification of catalytic active sites still remains challenging,inhibiting the rational design of excellent FeV-based catalysts.Here,in this work,a series of FeV catalysts with various compositions,including FeVO_(4),isolated VO_(x),low-polymerized V_(n)O_(x),and crystalline V_(2)O_(5) were prepared by controlling the preparation conditions,and were applied to methanol oxidation to formaldehyde reaction.A FeV_(1.1) catalyst,which consisted of FeVO_(4) and low-polymerized V_(n)O_(x) species showed an excellent catalytic performance with a methanol conversion of 92.3%and a formaldehyde selectivity of 90.6%,which was comparable to that of conventional iron-molybdate catalyst.The results of CH_(3)OH-IR,O_(2) pulse and control experiments revealed a crucial synergistic effect between FeVO_(4) and low-polymerized V_(n)O_(x).It enhanced the oxygen supply capacity and suitable binding and adsorption strengths for formaldehyde intermediates,contributing to the high catalytic activity and formaldehyde selectivity.This study not only advances the understanding of FeV structure but also offers valuable guidelines for selective methanol oxidation to formaldehyde.
文摘CuZn-based catalyst is an attractive catalyst for methanol synthesis from CO_(2)hydrogenation,but it early deactivates and its methanol yield still needs to improve.In this study,Y_(2)O_(3)was introduced to Cu/ZnO using a one-pot hydrothermal method,and exhibits a synergistic effect of ZnO and Y_(2)O_(3)on enhancing methanol yield and the stability.We found that the interaction between Y_(2)O_(3)and ZnO results in abundant oxygen vacancies formation,thereby enhancing CO_(2)adsorption and activation.Kinetic analysis and in situ DRIFTS suggest that RWGS forming CO and methanol formation compete for a mutual intermediate HCOO^(*),and the introduction of Y_(2)O_(3)to Cu/ZnO raises the energy barrier for the CO formation but lowers that for methanol formation,thus enhancing the methanol yield on Cu/ZnO/Y_(2)O_(3).
基金supported by the National Natural Science Foundation of China(No.22208322)the Natural Science Foundation of Henan(No.242300421230)+1 种基金the Key Research Projects of Higher Education Institutions of Henan Province(No.24A530009)the Special Fund for Young Teachers from Zhengzhou University(No.JC23257011).
文摘Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.
基金the financial support from National Science Centre Poland(NCN)based on the decision number UMO-2021/43/D/ST5/00824financial support of research project supported by the program“Excellence Initiative-Research University”for the AGH University of Krakow.
文摘The electrochemical conversion of carbon dioxide into valuable products is pivotal for maintaining the global carbon cycle and mitigating global warming.This review explores the advancements in electrochemical CO_(2) conversion,particularly focusing on producing methanol,ethanol,and n-propanol using various catalysts such as metals,metal oxides,metal alloys,and metal organic frameworks.Additionally,it covers the photoelectrochemical(PEC)conversion of CO_(2) into alcohols.The primary objective is to identify efficient electrocatalysts for ethanol,methanol,and n-propanol production,prioritizing selectivity,stability,Faradaic efficiency(FE),and current density.Notable catalysts include PtxZn nanoalloys,which exhibit an FE of~81.4% for methanol production,and trimetallic Pt/Pb/Zn nanoalloys,aimed at reducing Pt costs while enhancing catalyst stability and durability.Metal oxide catalysts like thin film Cu_(2)O/CuO on nickel foam and Cu_(2)O/ZnO achieve FE values of~38% and~16.6% for methanol production,respectively.Copper-based metal-organic frameworks,such as Cu@Cu_(2)O,demonstrate an FE of~45% for methanol production.Similarly,Ag_(0.14)/Cu_(0.86) and Cu-Zn alloys exhibit FEs of~63% and~46.6%,respectively,for ethanol production.Notably,n-propanol production via Pd–Cu alloy and graphene/ZnO/Cu_(2)O yields FEs of~13.7% and~23%,respectively.Furthermore,the review discusses recent advancements in PEC reactor design,photoelectrodes,reaction mechanisms,and catalyst durability.By evaluating the efficiency of these devices in liquid fuel production,the review addresses challenges and prospects in CO_(2) conversion for obtaining various valuable products.
基金the financial support from the European Commission through the H2020-MSCA-RISE-2020 BIOALL project(Grant Agreement: 101008058)。
文摘Single carbon products(C1 compounds) are simple but important chemicals in the road towards energy transition.Catalytic conversion of CO_(2) with H_(2)(desirably renewable) can be performed over reducible oxides supporting transition metals to obtain products such as CH_(4),CO and MeOH.Oxygen vacancies(O-vacancies),which are inherent defects of reducible metal oxides,play an enormous role in driving the catalytic performance(activity,selectivity,stability) for the desired reactions.Yet,the assessment of O-defects at realistic conditions is often complex.Only few techniques can provide direct evidence for their existence and influence in CO_(2) activation.Among them,electron paramagnetic spectroscopy(EPR),Raman spectroscopy,scanning probe microscopies(SPM) and environmental transmission electron microscopy(ETEM) are nowadays the most informative.In most cases,however,the measurements require reaction conditions far away from CO_(2) valorization applications.Although great efforts have been fruitful in explaining and demonstrating the huge importance of O-vacancies in CO_(2) catalysis,still ambiguous or erroneous interpretations about structure-function correlations involving O-vacancies are found in literature,especially,when information is not properly gathered,e.g.,by O 1s ex-situ X-ray photon spectroscopy(XPS).Moreover,despite the recognized importance of O-vacancies for CO_(2) valorization,critical literature compilations about their effects in thermal processes are scarce.Herein,we attempt to contribute in closing this gap by integrally encompassing representative investigations on the thermo-catalytic production of CH_(4),CO and MeOH.Particularly,we emphasize on the proper selection of assessment tools(direct/indirect) to unambiguously establish structure-function relationships to design optimized O-defective catalysts for the targeted compounds.
