Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitro...Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.展开更多
The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate ...The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.展开更多
Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of ni...Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of nitrogen-containing hypercrosslinked fer-rocene polymer precursors(HCP-FCs).Subsequent carbonization of these precursors results in the production of iron-nitrogen-doped por-ous carbon absorbers(Fe-NPCs).The Fe-NPCs demonstrate a porous structure comprising aggregated nanotubes and nanospheres.The porosity of this structure can be modulated by adjusting the iron and nitrogen contents to optimize impedance matching.The uniform dis-tribution of Fe-N_(x)C,N dipoles,andα-Fe within the carbon matrix can be ensured by using hypercrosslinked ferrocenes in constructing porous carbon,providing the absorber with numerous polarization sites and a conductive network.The electromagnetic wave absorption performance of the specially designed Fe-NPC-M_(2)absorbers is satisfactory,revealing a minimum reflection loss of-55.3 dB at 2.5 mm and an effective absorption bandwidth of 6.00 GHz at 2.0 mm.By utilizing hypercrosslinked polymers(HCPs)as precursors,a novel method for developing highly efficient carbon-based absorbing agents is introduced in this research.展开更多
K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require f...K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.展开更多
The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-d...The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.展开更多
Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to S...Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to SOC across a wide range of N addition rates,remain elusive.In a temperate grassland with six years'consecutive N addition spanning seven rates(0-50 g N/(m^(2)·year))in Inner Mongolia,China,we explored the responses of soil MNC and its contribution to SOC.The soil MNC showed a hump-shaped pattern to increasing N addition rates,with the N saturation threshold at 18.07 g N/(m^(2)·year).The soil MNC was driven by nematode abundance and the ratio of bacterial to fungal biomass below the N threshold,and by plant biomass allocation pattern and diversity above the N threshold.The contribution of soil MNC to SOC declined with increasing N addition rates,and was mainly regulated by the ratio of MNC to mineral-associated organic carbon and plant diversity and the ratio of bacterial to fungal biomass.In addition,the soil MNC and SOC differentially responded to N addition and were mediated by disparate biological and geochemical mechanisms,leading to the decoupled MNC production from SOC formation.Together,in this N-enriched temperate grassland,the soilmicrobial necro-mass production tends to be insufficient as a general explanation linking SOC formation.This study expands the mechanistic comprehension of the connections between external N input and soil carbon sequestration.展开更多
Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and ...Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.展开更多
Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation d...Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cyde performance,unbeneficial for the application as fast-charging and long-cycling SIBs anode.Herein,the three-dimensional porous Cu_(1.81)S/nitrogen-doped carbon frameworks(Cu_(1.81)S/NC)are synthesized by the simple and facile sol-gel and annealing processes,which can accommodate the volumetric expansion of Cu_(1.81)S nanoparticles and accelerate the transmission of ions and electrons during Na^(+)insertion/extraction processes,exhibiting the excellent rate capability(250.6 mA·g^(-1)at 20.0 A·g^(-1))and outstanding cycling stability(70% capacity retention for 6000 cycles at 10.0 A·g^(-1))for SIBs.Moreover,the Na-ion full cells coupled with Na_(3)V_(2)(PO_(4))_(3)/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh·g^(-1)at 5.0 A·g^(-1)and long-cycle performance with the 86.9% capacity retention at 2.0 A·g^(-1)after 750 cycles.This work proposes a promising way for the conversionbased metal sulfides for the applications as fast-charging sodium-ion battery anode.展开更多
Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption metho...Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption method is the most effective and convenient method. The adsorption amount of traditional activated carbon is limited, so it needs to be modified to improve the adsorption rate. This experiment determined a reasonable modification method, and the calcination method was selected for the modification. This paper mainly compares the surface morphological characteristics of activated carbon before and after modification. The modified X-ray diffraction peak is increased and the infrared ray absorption peak increased, and the results show that the surface of the modified activated carbon is more rough than that of the modified activated carbon, the functional groups are increased, and the sulfur and nitrogen are doped on the activated carbon. Therefore, the modified activated carbon has a high removal rate and the best performance under acidic conditions.展开更多
In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to sign...In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to significant environmental issues[1].Currently,sustainable biomass resources have attracted much attention as potential substitutes to fossil fuels for producing biofuels and commodity chemicals[2].展开更多
Dual atomic catalysts(DAC),particularly copper(Cu_(2))-based nitrogen(N)doped graphene,show great potential to effectively convert CO_(2)and nitrate(NO_(3)-)into important industrial chemicals such as ethylene,glycol,...Dual atomic catalysts(DAC),particularly copper(Cu_(2))-based nitrogen(N)doped graphene,show great potential to effectively convert CO_(2)and nitrate(NO_(3)-)into important industrial chemicals such as ethylene,glycol,acetamide,and urea through an efficient catalytical process that involves C–C and C–N coupling.However,the origin of the coupling activity remained unclear,which substantially hinders the rational design of Cu-based catalysts for the N-integrated CO_(2)reduction reaction(CO_(2)RR).To address this challenge,this work performed advanced density functional theory calculations incorporating explicit solvation based on a Cu_(2)-based N-doped carbon(Cu_(2)N_(6)C_(10))catalyst for CO_(2)RR.These calculations are aimed to gain insight into the reaction mechanisms for the synthesis of ethylene,acetamide,and urea via coupling in the interfacial reaction micro-environment.Due to the sluggishness of CO_(2),the formation of a solvation electric layer by anions(F^(-),Cl^(-),Br^(-),and I^(-))and cations(Na+,Mg^(2+),K+,and Ca^(2+))leads to electron transfer towards the Cu surface.This process significantly accelerates the reduction of CO_(2).These results reveal that*CO intermediates play a pivotal role in N-integrated CO_(2)RR.Remarkably,the Cu_(2)-based N-doped carbon catalyst examined in this study has demonstrated the most potential for C–N coupling to date.Our findings reveal that through the process of a condensation reaction between*CO and NH_(2)OH for urea synthesis,*NO_(3)-is reduced to*NH_(3),and*CO_(2)to*CCO at dual Cu atom sites.This dual-site reduction facilitates the synthesis of acetamide through a nucleophilic reaction between NH_(3)and the ketene intermediate.Furthermore,we found that the I-and Mg^(2+)ions,influenced by pH,were highly effective for acetamide and ammonia synthesis,except when F-and Ca^(2+)were present.Furthermore,the mechanisms of C–N bond formation were investigated via ab-initio molecular dynamics simulations,and we found that adjusting the micro-environment can change the dominant side reaction,shifting from hydrogen production in acidic conditions to water reduction in alkaline ones.This study introduces a novel approach using ion-H_(2)O cages to significantly enhance the efficiency of C–N coupling reactions.展开更多
The major problem with lithium-sulfur(Li-S)batteries is their poor cycling stability because of slow redox kinetics in the cathode and the growth of lithium dendrites on the anode.We report the production of 2D porous...The major problem with lithium-sulfur(Li-S)batteries is their poor cycling stability because of slow redox kinetics in the cathode and the growth of lithium dendrites on the anode.We report the production of 2D porous carbon nanosheets doped with both Fe and Ni(Fe/Ni-N-PCNSs)by an easy and template-free approach that solve this problem.Because of their ultrathin porous 2D structure and uniform distribution of Fe and Ni dopants,they capture polysulfides,speed up the sulfur redox reaction,and improve the material’s lithiophilicity,greatly suppressing the shuttling of polysulfides and dendrite growth on the lithium anode.As a result,it has an exceptional performance as a stable host for elemental sulfur and metallic lithium,producing a record long life of 1000 cycles with a very small capacity decay of 0.00025%per cycle in a Li-S battery and an excellent cycling stability of over 850 h with a small overpotential of>72 mV in a lithium metal battery.This work suggests the use of multifunctional-based 2D porous carbon nanosheets as a stable host for both elemental sulfur and metallic lithium to improve the Li-S battery per-formance.展开更多
Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NH...Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.展开更多
Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping...Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.展开更多
Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely us...Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely used in energy storage devices for the enhanced electrochemical performance.Herein,B and P co-doped flexible carbon nanofibers with nitrogen-rich(B-P/NC)are investigated with electro-spinning for sodium-ion battery.The flexible of binderless B-P/NC with annealing of 600℃(B-P/NC-600)exhibits the remarkable performance for the robust capacity of 200 mAh/g at 0.1 A/g after 500 cycles and a durable reversible capacity of 160 m Ah/g even at 1 A/g after 12,000 cycles,exhibiting the equally commendable stability of flexible B-P/NC-600.In addition,B-P/NC-600 delivers the reversible capacity of265 m Ah/g with the test temperature of 60℃.More importantly,the flexible B-P/NC-600 is fabricated as anode for the whole battery,delivering the capacity of 90 m Ah/g at 1 A/g after 200 cycles.Meanwhile,theoretical calculation further verified that boron and phosphorus co-doping can improve the adsorption capacity of nitrogen carbon materials.The favorable performance of flexible B-P/NC-600 can be ascribed to the nitrogen-rich carbon nanofibers with three-dimensional network matrix for the more active site of boron and phosphorus co-doping.Our work paves the way for the improvement of flexible anodes and wide-operating temperature of sodium-ion batteries by doping approach of much heteroatom.展开更多
Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary ca...Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.展开更多
Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs...Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.展开更多
Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mer...Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.展开更多
We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanopartic...We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.展开更多
Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost...Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.展开更多
基金supported by the National Natural Science Foundation of China(52321005)the Guangdong Basic and Applied Basic Research Foundation(2023A1515012383 and 2024A1515030138)+1 种基金the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology,2021TS30)the Shenzhen Science and Technology Program(KQTD20190929172630447 and KCXFZ20211020163404007).
文摘Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.42425107)Ecological Civilization Special Project of Key Research&and Development Program in Gansu Province(No.24YFFA009)the Top Talent Project of Gansu Province,Chinese Academy of Sciences Young Crossover Team Project(No.JCTD-2022-18)。
文摘The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.
基金supported by the National Natural Science Foundation of China(No.51803041)the University and Local Integration Development Project of Yantai,China(No.2022 XDRHXMXK08).
文摘Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of nitrogen-containing hypercrosslinked fer-rocene polymer precursors(HCP-FCs).Subsequent carbonization of these precursors results in the production of iron-nitrogen-doped por-ous carbon absorbers(Fe-NPCs).The Fe-NPCs demonstrate a porous structure comprising aggregated nanotubes and nanospheres.The porosity of this structure can be modulated by adjusting the iron and nitrogen contents to optimize impedance matching.The uniform dis-tribution of Fe-N_(x)C,N dipoles,andα-Fe within the carbon matrix can be ensured by using hypercrosslinked ferrocenes in constructing porous carbon,providing the absorber with numerous polarization sites and a conductive network.The electromagnetic wave absorption performance of the specially designed Fe-NPC-M_(2)absorbers is satisfactory,revealing a minimum reflection loss of-55.3 dB at 2.5 mm and an effective absorption bandwidth of 6.00 GHz at 2.0 mm.By utilizing hypercrosslinked polymers(HCPs)as precursors,a novel method for developing highly efficient carbon-based absorbing agents is introduced in this research.
基金financially supported by the Materials/Parts Technology Development Program(No.RS-202400456324)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)by the National Research Foundation(NRF)of Korea grant(No.RS-2024-00454367)funded by the Ministry of Science and ICT(MSIT,Korea)。
文摘K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.
基金Project supported by the National Natural Science Foundation of China(22102141)。
文摘The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.
基金supported by the National Natural Science Foundation of China(Nos.42130515 and 32301450)the Open Foundation of State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences.
文摘Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to SOC across a wide range of N addition rates,remain elusive.In a temperate grassland with six years'consecutive N addition spanning seven rates(0-50 g N/(m^(2)·year))in Inner Mongolia,China,we explored the responses of soil MNC and its contribution to SOC.The soil MNC showed a hump-shaped pattern to increasing N addition rates,with the N saturation threshold at 18.07 g N/(m^(2)·year).The soil MNC was driven by nematode abundance and the ratio of bacterial to fungal biomass below the N threshold,and by plant biomass allocation pattern and diversity above the N threshold.The contribution of soil MNC to SOC declined with increasing N addition rates,and was mainly regulated by the ratio of MNC to mineral-associated organic carbon and plant diversity and the ratio of bacterial to fungal biomass.In addition,the soil MNC and SOC differentially responded to N addition and were mediated by disparate biological and geochemical mechanisms,leading to the decoupled MNC production from SOC formation.Together,in this N-enriched temperate grassland,the soilmicrobial necro-mass production tends to be insufficient as a general explanation linking SOC formation.This study expands the mechanistic comprehension of the connections between external N input and soil carbon sequestration.
基金financially supported by the National Natural Science Foundation of China(Nos.12175089 and 12205127)the Key Research and Development Program of Yunnan Province,China(Nos.202301AU070064 and 202103AF140006)the Yunnan Industrial Innovative Talents Program for“Xingdian Talent Support Plan”,China(No.KKXY202252001).
文摘Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.
基金financially supported by the National Natural Science Foundation of China(Nos.U1904173 and 52272219)the Key Research Projects of Henan Provincial Department of Education(No.19A150043)+2 种基金the Natural Science Foundation of Henan Province(Nos.202300410330 and 222300420276)the Nanhu Scholars Program for Young Scholars of Xinyang Normal Universitythe Xinyang Normal University Analysis&Testing Center。
文摘Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cyde performance,unbeneficial for the application as fast-charging and long-cycling SIBs anode.Herein,the three-dimensional porous Cu_(1.81)S/nitrogen-doped carbon frameworks(Cu_(1.81)S/NC)are synthesized by the simple and facile sol-gel and annealing processes,which can accommodate the volumetric expansion of Cu_(1.81)S nanoparticles and accelerate the transmission of ions and electrons during Na^(+)insertion/extraction processes,exhibiting the excellent rate capability(250.6 mA·g^(-1)at 20.0 A·g^(-1))and outstanding cycling stability(70% capacity retention for 6000 cycles at 10.0 A·g^(-1))for SIBs.Moreover,the Na-ion full cells coupled with Na_(3)V_(2)(PO_(4))_(3)/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh·g^(-1)at 5.0 A·g^(-1)and long-cycle performance with the 86.9% capacity retention at 2.0 A·g^(-1)after 750 cycles.This work proposes a promising way for the conversionbased metal sulfides for the applications as fast-charging sodium-ion battery anode.
文摘Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption method is the most effective and convenient method. The adsorption amount of traditional activated carbon is limited, so it needs to be modified to improve the adsorption rate. This experiment determined a reasonable modification method, and the calcination method was selected for the modification. This paper mainly compares the surface morphological characteristics of activated carbon before and after modification. The modified X-ray diffraction peak is increased and the infrared ray absorption peak increased, and the results show that the surface of the modified activated carbon is more rough than that of the modified activated carbon, the functional groups are increased, and the sulfur and nitrogen are doped on the activated carbon. Therefore, the modified activated carbon has a high removal rate and the best performance under acidic conditions.
基金funded by the Master,PhD Scholarship Programme of Vingroup Innovation Foundation(VINIF),code VINIF.2024.TS.035funded by Vietnam National University,Ho Chi Minh City(VNUHCM)under grant number NCM2024-18-01。
文摘In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to significant environmental issues[1].Currently,sustainable biomass resources have attracted much attention as potential substitutes to fossil fuels for producing biofuels and commodity chemicals[2].
基金National Natural Science Foundation of China(U22B20149,22308376)Outstanding Young Scholars Foundation of China University of Petroleum(Beijing)(2462023BJRC015)Foundation of United Institute for Carbon Neutrality(CNIF20230209)。
文摘Dual atomic catalysts(DAC),particularly copper(Cu_(2))-based nitrogen(N)doped graphene,show great potential to effectively convert CO_(2)and nitrate(NO_(3)-)into important industrial chemicals such as ethylene,glycol,acetamide,and urea through an efficient catalytical process that involves C–C and C–N coupling.However,the origin of the coupling activity remained unclear,which substantially hinders the rational design of Cu-based catalysts for the N-integrated CO_(2)reduction reaction(CO_(2)RR).To address this challenge,this work performed advanced density functional theory calculations incorporating explicit solvation based on a Cu_(2)-based N-doped carbon(Cu_(2)N_(6)C_(10))catalyst for CO_(2)RR.These calculations are aimed to gain insight into the reaction mechanisms for the synthesis of ethylene,acetamide,and urea via coupling in the interfacial reaction micro-environment.Due to the sluggishness of CO_(2),the formation of a solvation electric layer by anions(F^(-),Cl^(-),Br^(-),and I^(-))and cations(Na+,Mg^(2+),K+,and Ca^(2+))leads to electron transfer towards the Cu surface.This process significantly accelerates the reduction of CO_(2).These results reveal that*CO intermediates play a pivotal role in N-integrated CO_(2)RR.Remarkably,the Cu_(2)-based N-doped carbon catalyst examined in this study has demonstrated the most potential for C–N coupling to date.Our findings reveal that through the process of a condensation reaction between*CO and NH_(2)OH for urea synthesis,*NO_(3)-is reduced to*NH_(3),and*CO_(2)to*CCO at dual Cu atom sites.This dual-site reduction facilitates the synthesis of acetamide through a nucleophilic reaction between NH_(3)and the ketene intermediate.Furthermore,we found that the I-and Mg^(2+)ions,influenced by pH,were highly effective for acetamide and ammonia synthesis,except when F-and Ca^(2+)were present.Furthermore,the mechanisms of C–N bond formation were investigated via ab-initio molecular dynamics simulations,and we found that adjusting the micro-environment can change the dominant side reaction,shifting from hydrogen production in acidic conditions to water reduction in alkaline ones.This study introduces a novel approach using ion-H_(2)O cages to significantly enhance the efficiency of C–N coupling reactions.
基金supported by Basic and Applied Basic Research Fund Project of Guangdong(2022A1515011817,2023A1515030160)Research and Innovation Group of Guangdong University of Education(2024KYCXTD014)。
文摘The major problem with lithium-sulfur(Li-S)batteries is their poor cycling stability because of slow redox kinetics in the cathode and the growth of lithium dendrites on the anode.We report the production of 2D porous carbon nanosheets doped with both Fe and Ni(Fe/Ni-N-PCNSs)by an easy and template-free approach that solve this problem.Because of their ultrathin porous 2D structure and uniform distribution of Fe and Ni dopants,they capture polysulfides,speed up the sulfur redox reaction,and improve the material’s lithiophilicity,greatly suppressing the shuttling of polysulfides and dendrite growth on the lithium anode.As a result,it has an exceptional performance as a stable host for elemental sulfur and metallic lithium,producing a record long life of 1000 cycles with a very small capacity decay of 0.00025%per cycle in a Li-S battery and an excellent cycling stability of over 850 h with a small overpotential of>72 mV in a lithium metal battery.This work suggests the use of multifunctional-based 2D porous carbon nanosheets as a stable host for both elemental sulfur and metallic lithium to improve the Li-S battery per-formance.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22278092,22078116 and 22222805)Guangdong Provincial Key Research and Development Program(No.2020B1111380002)+2 种基金Science and Technology Research Project of Guangzhou(Nos.2023A03J0034,2023A04J0077 and 202102020467)State Key Laboratory of Pulp and Paper Engineering(No.202313)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464).
文摘Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.
基金supported by the National Natural Science Foundation of China(22262010,22062005,22165005,U20A20128)Guangxi Science and Technology Fund for Distinguished HighTalent Introduction Program(AC22035091)Guangxi Science Fund for Distinguished Young Scholars(2019GXNSFFA245016)。
文摘Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.
基金supported by Natural Science Foundation of China(No.6230031623)the Natural Science Foundation of Hunan Province(No.2024JJ5127)+2 种基金the Education Department of Hunan Province(No.22B0580)the Scientific Research and Innovation Foundation of Hunan University of Technology(No.CX2317)the Innovation and Entrepreneurship Training Project for College Students(No.S202311535061)。
文摘Flexible energy storage devices have been paid much attention and adapts to apply in various fields.Benefiting from the active sites of boron(B)and phosphorus(P)doping materials,co-doped carbon materials are widely used in energy storage devices for the enhanced electrochemical performance.Herein,B and P co-doped flexible carbon nanofibers with nitrogen-rich(B-P/NC)are investigated with electro-spinning for sodium-ion battery.The flexible of binderless B-P/NC with annealing of 600℃(B-P/NC-600)exhibits the remarkable performance for the robust capacity of 200 mAh/g at 0.1 A/g after 500 cycles and a durable reversible capacity of 160 m Ah/g even at 1 A/g after 12,000 cycles,exhibiting the equally commendable stability of flexible B-P/NC-600.In addition,B-P/NC-600 delivers the reversible capacity of265 m Ah/g with the test temperature of 60℃.More importantly,the flexible B-P/NC-600 is fabricated as anode for the whole battery,delivering the capacity of 90 m Ah/g at 1 A/g after 200 cycles.Meanwhile,theoretical calculation further verified that boron and phosphorus co-doping can improve the adsorption capacity of nitrogen carbon materials.The favorable performance of flexible B-P/NC-600 can be ascribed to the nitrogen-rich carbon nanofibers with three-dimensional network matrix for the more active site of boron and phosphorus co-doping.Our work paves the way for the improvement of flexible anodes and wide-operating temperature of sodium-ion batteries by doping approach of much heteroatom.
基金supported by the National Key Research and Development Program of China(2021YFD1300201)the National Natural Science Foundation of China(32330100 and 32125036)+3 种基金the China Agricultural Research System(CARS-35)2115 Talent Development Program of China Agricultural Universitythe 111 Project(No.B16044)the 2023 Key Project of the Graduate Independent Innovation Research Fund at China Agricultural University。
文摘Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.
基金supported by the National Key Research and Development Project of China(No.2022YFE0113800)the National Natural Science Foundation of China(No.22102013)+2 种基金Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0945)Venture and Innovation Support Program for Chongqing Overseas Returnees(No.cx2020107)Thousand Talents Program for Distinguished Young Scholars,Postdoctoral Fellowship Program of CPSF(No.GZB20230910)。
文摘Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.
基金supported by the National Key Research and Development Program of China(2024YFC3907904).
文摘Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.
基金supported by the National Natural Science Foundation of China(21503264,22179081 and 22076117)Natural Science Foundation of Shanghai(20ZR1422500).
文摘We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.
基金sponsored by the National Natural Science Foundation of China(Nos.U23A6005 and 22178069)。
文摘Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.
