Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The h...Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.展开更多
Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are suscept...Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are susceptible to external interferences and, thus, cannot meet the increasingly strict monitoring needs of a complex air-conducting pipeline system of an aircraft. In view of this point, this paper studies an alternative sensor system based on a dense array fiber grating. To obtain a compact and light-weight airborne signal processing system, a field programmable gate array is used as the main control core that controls the output of the light source. The functions of pulse modulation, analog-to-digital conversion,data buffering and transmission are integrated into a single system, while the linear sensing monitoring is obtained by detecting the time-division and wavelength-division wavelength drift signals of the fiber Bragg grating array. Our experiments show that the spatial resolution of the linear sensing system approaches 5 cm, the temperature measurement accuracy reaches 2 ℃, the temperature measurement range is between 0–250 ℃, and the response time is within 4 s. Compared with the existing electrical monitoring systems, various monitoring indicators have been greatly improved and have broad application prospects.展开更多
Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous ...Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.展开更多
Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production...Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production in direct water splitting.In this work,large current and high efficiency of EOR on a Ni,Fe layered double hydroxide(NiFe-LDH)catalyst were simultaneously achieved by a facile fluorination strategy.F in NiFe-LDH can reduce the activation energy of the dehydrogenation reaction,thus promoting the deprotonation process of NiFe-LDH to achieve a lower EOR onset potential.It also weakens the absorption of OH-and nucleophile electrooxidation products on the surface of NiFe-LDH at a higher potential,achieving a high current density and EOR selectivity,according to density functional theory calculations.Based on our experiment results,the optimized fluorinated NiFe-LDH catalyst achieves a low potential of 1.386 V to deliver a 10 mA cm^(-2)EOR.Moreover,the Faraday efficiency is greater than 95%,with a current density ranging from 10 to 250 mA cm^(-2).This work provides a promising pathway for an efficient and cost-effective NOR catalyst design for economic hydrogen production.展开更多
RNAs play crucial and versatile roles in cellular biochemical reactions.Since experimental approaches of determining their three-dimensional(3D)structures are costly and less efficient,it is greatly advantageous to de...RNAs play crucial and versatile roles in cellular biochemical reactions.Since experimental approaches of determining their three-dimensional(3D)structures are costly and less efficient,it is greatly advantageous to develop computational methods to predict RNA 3D structures.For these methods,designing a model or scoring function for structure quality assessment is an essential step but this step poses challenges.In this study,we designed and trained a deep learning model to tackle this problem.The model was based on a graph convolutional network(GCN)and named RNAGCN.The model provided a natural way of representing RNA structures,avoided complex algorithms to preserve atomic rotational equivalence,and was capable of extracting features automatically out of structural patterns.Testing results on two datasets convincingly demonstrated that RNAGCN performs similarly to or better than four leading scoring functions.Our approach provides an alternative way of RNA tertiary structure assessment and may facilitate RNA structure predictions.RNAGCN can be downloaded from https://gitee.com/dcw-RNAGCN/rnagcn.展开更多
Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness o...Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.展开更多
Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction(EOR)play a crucial role in the commercialization of direct ethanol fuel cells(DEFCs).However,the poisonous intermediates(especially ad...Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction(EOR)play a crucial role in the commercialization of direct ethanol fuel cells(DEFCs).However,the poisonous intermediates(especially adsorbed CO species(COad))formed during the EOR process can easily adsorb and block the active sites on Pd electrodes,which in turn limits the catalytic efficiency.Hence,we present a series of Pd-based composites with a strong coupling interface consisting of Pd nanosheets and amorphous Bi(OH)_(3)species.The incorporation of Bi(OH)3 can induce an electron-rich state adjacent to the Pd sites and effectively separate the Pd ensemble,leading to excellent CO tolerance.The optimal Pd-Bi(OH)_(3)NSs catalyst manifests a mass activity of 2.2 A·mgPd^(-1),which is 5.7 and 2.0 times higher than that of Pd NSs and commercial Pd/C catalyst,respectively.Further CO-stripping experiments and CO-DRIFTS tests confirm the excellent CO tolerance on Pd-Bi(OH)3 NSs electrode,leading to the enhanced EOR durability.展开更多
Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte inte...Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte interface and on the resultant mass transport within the hydrodynamic boundary layer in the vicinity of the cathode.To resolve the complex local reaction environment of branching CO_(2)reduction pathways,we here present a dif-ferential electrochemical mass spectroscopic(DEMS)approach for Cu electrodes to investigate CO_(2)mass trans-port,the local concentration gradients of buffering anions,and the Cu surface topology effects on CO_(2)electrolysis selectivity at a temporal resolution of~400 ms.As a proof of concept,these tuning knobs were validated on an anion exchange membrane electrolyzer,which delivered a Faradaic efficiency of up to 40.4%and a partial current density of 121 mA cm^(-2)for CO_(2)-to-C_(2)H_(4)valorization.This methodology,which bridges the study of fundamental surface electrochemistry and the upgrading of practical electrolyzer performance,could be of general interest in helping to achieve a sustainable circular carbon economy.展开更多
The utilization of single atoms(SAs)as trifunctional electrocatalyst for nitro-gen reduction,oxygen reduction,and oxygen evolution reactions(NRR,ORR,and OER)is still a formidable challenge.Herein,we devise one-pot syn...The utilization of single atoms(SAs)as trifunctional electrocatalyst for nitro-gen reduction,oxygen reduction,and oxygen evolution reactions(NRR,ORR,and OER)is still a formidable challenge.Herein,we devise one-pot synthesized palladium SAs stabilized on nitrogen-doped carbon palladium SA electrocat-alyst(Pd-SA/NC)as efficient trifunctional electrocatalyst for NRR,ORR,and OER.Pd-SA/NC performs a robust catalytic activity toward NRR with faradaic efficiency of 22.5%at-0.25 V versus reversible hydrogen electrode(RHE),and the relative Pd utilization efficiency is enhanced by 17-fold than Pd-NP/NC.In addition,the half-wave potential reaches 0.876 V versus RHE,amounting to a 58-time higher mass activity than commercial Pt/C.Moreover,the overpotential at 10 mA cm-2 is as low as 287 mV for Pd-SA/NC,outperforming the commer-cial IrO2 by 360 times in turnover frequency at 1.6 V versus RHE.Accordingly,the assembled rechargeable zinc-air battery(ZAB)achieves a maximum power den-sity of 170 mW cm-2,boosted by 2.3 times than Pt/C–IrO2.Two constructed ZABs efficiently power the NRR-OER system to electrochemically generate ammonia implying its superior trifunctionality.展开更多
In the pursuit of sustainable energy solutions,the efficiency of the hydrogen evolution reaction(HER)in alkaline conditions has been a significant challenge,primarily due to the sluggish dissociation of water molecule...In the pursuit of sustainable energy solutions,the efficiency of the hydrogen evolution reaction(HER)in alkaline conditions has been a significant challenge,primarily due to the sluggish dissociation of water molecules on platinum(Pt)catalysts.Addressing this critical issue,our study introduces an innovative Pt-Co@NCS catalyst.This catalyst synergistically combines Pt nanoparticles with Co single atoms on a nitrogen-doped carbon scaffold,overcoming the traditional bottleneck of slow water dissociation.Its unique porous concave structure and nitrogen-enriched surface not only provide abundant anchoring sites for Co atoms but also create a conducive hydrophilic environment around the Pt particles.This design leads to a drastic improvement in the water dissociation process,as demonstrated by CO stripping and deuterium labeling experiments.Achieving an outstanding current density of 162.8 mA cm^(−2) at−0.1 V versus RHE,a Tafel slope of 26.2 mV dec^(−1),and a superior nominal mass activity of 15.75 mAμgPt^(−1),the Pt-Co@NCS catalyst represents a significant step forward in enhancing alkaline HER efficiency,indicating promising advancements in the field.展开更多
Carbon-free electrochemical nitrogen reduction reaction(NRR)is an appealing strategy for green ammonia synthesis,but there is still a significant performance bottleneck.Conventional working electrode is usually floode...Carbon-free electrochemical nitrogen reduction reaction(NRR)is an appealing strategy for green ammonia synthesis,but there is still a significant performance bottleneck.Conventional working electrode is usually flooded by the electrolyte during the NRR test,and only the surface material could get access to the nitrogen,which inevitably gives rise to sluggish reaction rate.Herein,an asymmetric electrode design is proposed to tackle this challenge.An aerophilic layer is constructed on one face of the electrocatalyst-loaded electrode,while the other side maintains its original structure,aiming to achieve facilitated nitrogen transfer and electrolyte permeation within the conductive skeleton simultaneously.This asymmetric architecture affords extensive threephase reaction region within the electrode as demonstrated by the combination of theoretical simulations and experimental measurements,which gives full play to the loaded electrocatalyst.As expected,the proofof-concept asymmetric electrode delivers an NH_(3)yield rate of 40.81μg h^(−1)mg^(−1)and a Faradaic efficiency of 71.71%at−0.3 V versus the reversible hydrogen electrode,which are more than 4 and 7 times that of conventional electrode,respectively.This work presents a versatile strategy for enhancing the interfacial reaction kinetics and is instructive to electrode design for gas-involved electrochemical reactions.展开更多
Electrochemical energy storage and conversion toward sustainable carbon neutrality cycle is of great interest in today's society.In this perspective,we highlight the interconversion between carbon dioxide and form...Electrochemical energy storage and conversion toward sustainable carbon neutrality cycle is of great interest in today's society.In this perspective,we highlight the interconversion between carbon dioxide and formic acid by means of electrocatalytic CO_(2)reduction reaction(CO_(2)RR)and formic acid oxidation reaction(FAOR)as an effective way to achieve that goal.In line with the distinctive catalytic nature of Pd to reversibly drive both FAOR and CO_(2)RR,we first illustrate the intimate mechanistic relation between these two reversed reactions over Pd surfaces.Next,recent advances in developing Pd-based bifunctional catalysts and relevant optimization strategies are briefly summarized,including geometric structure engineering with preferential facet exposure,construction of crystallographic ordering intermetallic,electronic structure manipulation through metal or metalloid doping to fine tune the binding strength for active and poisoning intermediates.At the end,our viewpoints on the design principles at both microscopic and macroscopic scales are offered toward an efficient CO_(2)and HCOOH interconversion loop.展开更多
基金We gratefully acknowledge support from the National Natural Science Foundation of China(Grant Nos.21905220,51772240,21503158,51425301,U1601214,21703184)the China Postdoctoral Science Foundation(2020M673408)+5 种基金the Key Research and Development Plan of Shaanxi Province,China(Grant No.2018ZDXM-GY-135)the Fundamental Research Funds for“Young Talent Support Plan”of Xi'an Jiaotong University(HG6J003)the“1000‐Plan program”of Shaanxi Province,the Promotion Program for Young and Middle-Aged Teacher in Science and Technology Research of Huaqiao University(ZQN-PY506)the Scientific Research Funds of Huaqiao University(17BS405)the State Key Laboratory for Mechanical Behavior of Materials(20192101)the Natural Science Foundation Committee of Jiangsu Province(BK20201190).
文摘Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.
文摘Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are susceptible to external interferences and, thus, cannot meet the increasingly strict monitoring needs of a complex air-conducting pipeline system of an aircraft. In view of this point, this paper studies an alternative sensor system based on a dense array fiber grating. To obtain a compact and light-weight airborne signal processing system, a field programmable gate array is used as the main control core that controls the output of the light source. The functions of pulse modulation, analog-to-digital conversion,data buffering and transmission are integrated into a single system, while the linear sensing monitoring is obtained by detecting the time-division and wavelength-division wavelength drift signals of the fiber Bragg grating array. Our experiments show that the spatial resolution of the linear sensing system approaches 5 cm, the temperature measurement accuracy reaches 2 ℃, the temperature measurement range is between 0–250 ℃, and the response time is within 4 s. Compared with the existing electrical monitoring systems, various monitoring indicators have been greatly improved and have broad application prospects.
基金supported by the National Natural Science Foundation of China(U21A20332,52103226,52202275,52203314,and 12204253)the Distinguished Young Scholars Fund of Jiangsu Province(BK20220061)the Fellowship of China Postdoctoral Science Foundation(2021M702382)。
文摘Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.
基金the financial support from the National Natural Science Foundation of China(22197121)Knowledge Innovation Program of Wuhan-Basic Research(2022010801010202)Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202201)。
文摘Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production in direct water splitting.In this work,large current and high efficiency of EOR on a Ni,Fe layered double hydroxide(NiFe-LDH)catalyst were simultaneously achieved by a facile fluorination strategy.F in NiFe-LDH can reduce the activation energy of the dehydrogenation reaction,thus promoting the deprotonation process of NiFe-LDH to achieve a lower EOR onset potential.It also weakens the absorption of OH-and nucleophile electrooxidation products on the surface of NiFe-LDH at a higher potential,achieving a high current density and EOR selectivity,according to density functional theory calculations.Based on our experiment results,the optimized fluorinated NiFe-LDH catalyst achieves a low potential of 1.386 V to deliver a 10 mA cm^(-2)EOR.Moreover,the Faraday efficiency is greater than 95%,with a current density ranging from 10 to 250 mA cm^(-2).This work provides a promising pathway for an efficient and cost-effective NOR catalyst design for economic hydrogen production.
基金funded by the National Natural Science Foundation of China(Grant Nos.11774158 to JZ,11934008 to WW,and 11974173 to WFL)。
文摘RNAs play crucial and versatile roles in cellular biochemical reactions.Since experimental approaches of determining their three-dimensional(3D)structures are costly and less efficient,it is greatly advantageous to develop computational methods to predict RNA 3D structures.For these methods,designing a model or scoring function for structure quality assessment is an essential step but this step poses challenges.In this study,we designed and trained a deep learning model to tackle this problem.The model was based on a graph convolutional network(GCN)and named RNAGCN.The model provided a natural way of representing RNA structures,avoided complex algorithms to preserve atomic rotational equivalence,and was capable of extracting features automatically out of structural patterns.Testing results on two datasets convincingly demonstrated that RNAGCN performs similarly to or better than four leading scoring functions.Our approach provides an alternative way of RNA tertiary structure assessment and may facilitate RNA structure predictions.RNAGCN can be downloaded from https://gitee.com/dcw-RNAGCN/rnagcn.
基金supported by the Youth Innovation Promotion Association(no.2015147)CAS and National Program on Key Basic Research Project(973 Program,2012CB215500)+1 种基金the Outstanding Youngest Scientist FoundationChinese Academy of Sciences(CAS)
文摘Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.
基金This work was supported by the National Natural Science Foundation of China(Nos.51922073 and 21902109)the Natural Science Foundation of Jiangsu Province(Nos.BK20200960 and BK20180097)+1 种基金the Natural Science Foundation of Higher Education in Jiangsu Province(No.20KJB150041)the Natural Science Foundation of Nantong University for High-Level Talent(No.03083033).
文摘Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction(EOR)play a crucial role in the commercialization of direct ethanol fuel cells(DEFCs).However,the poisonous intermediates(especially adsorbed CO species(COad))formed during the EOR process can easily adsorb and block the active sites on Pd electrodes,which in turn limits the catalytic efficiency.Hence,we present a series of Pd-based composites with a strong coupling interface consisting of Pd nanosheets and amorphous Bi(OH)_(3)species.The incorporation of Bi(OH)3 can induce an electron-rich state adjacent to the Pd sites and effectively separate the Pd ensemble,leading to excellent CO tolerance.The optimal Pd-Bi(OH)_(3)NSs catalyst manifests a mass activity of 2.2 A·mgPd^(-1),which is 5.7 and 2.0 times higher than that of Pd NSs and commercial Pd/C catalyst,respectively.Further CO-stripping experiments and CO-DRIFTS tests confirm the excellent CO tolerance on Pd-Bi(OH)3 NSs electrode,leading to the enhanced EOR durability.
基金supported by the National Key R&D Program of China(2022YFB4102000,2022YFA1505100,2022YFA1503803)the NSFC(22002088)+1 种基金the Shanghai Sailing Program(20YF1420500)the Shanghai Science and Technology Innovation Action Plan(22dz1205500).
文摘Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte interface and on the resultant mass transport within the hydrodynamic boundary layer in the vicinity of the cathode.To resolve the complex local reaction environment of branching CO_(2)reduction pathways,we here present a dif-ferential electrochemical mass spectroscopic(DEMS)approach for Cu electrodes to investigate CO_(2)mass trans-port,the local concentration gradients of buffering anions,and the Cu surface topology effects on CO_(2)electrolysis selectivity at a temporal resolution of~400 ms.As a proof of concept,these tuning knobs were validated on an anion exchange membrane electrolyzer,which delivered a Faradaic efficiency of up to 40.4%and a partial current density of 121 mA cm^(-2)for CO_(2)-to-C_(2)H_(4)valorization.This methodology,which bridges the study of fundamental surface electrochemistry and the upgrading of practical electrolyzer performance,could be of general interest in helping to achieve a sustainable circular carbon economy.
基金National Natural Science Foundation of China,Grant/Award Numbers:22209126,22279095Shccig-Qinling Program。
文摘The utilization of single atoms(SAs)as trifunctional electrocatalyst for nitro-gen reduction,oxygen reduction,and oxygen evolution reactions(NRR,ORR,and OER)is still a formidable challenge.Herein,we devise one-pot synthesized palladium SAs stabilized on nitrogen-doped carbon palladium SA electrocat-alyst(Pd-SA/NC)as efficient trifunctional electrocatalyst for NRR,ORR,and OER.Pd-SA/NC performs a robust catalytic activity toward NRR with faradaic efficiency of 22.5%at-0.25 V versus reversible hydrogen electrode(RHE),and the relative Pd utilization efficiency is enhanced by 17-fold than Pd-NP/NC.In addition,the half-wave potential reaches 0.876 V versus RHE,amounting to a 58-time higher mass activity than commercial Pt/C.Moreover,the overpotential at 10 mA cm-2 is as low as 287 mV for Pd-SA/NC,outperforming the commer-cial IrO2 by 360 times in turnover frequency at 1.6 V versus RHE.Accordingly,the assembled rechargeable zinc-air battery(ZAB)achieves a maximum power den-sity of 170 mW cm-2,boosted by 2.3 times than Pt/C–IrO2.Two constructed ZABs efficiently power the NRR-OER system to electrochemically generate ammonia implying its superior trifunctionality.
基金support from the National Natural Science Foundation of China(22379120,22350410375)the University Development Fund,Research Start-up Fund(UDF01002976)from the Chinese University of Hong Kong(Shenzhen)+2 种基金the Higher Education Institution Academic Discipline Innovation and Talent Introduction Plan(111 Plan)(No.B23025)the Shenzhen Science and Technology Program(JCYJ20230807114302005)the China Postdoctoral Science Foundation(2020M673408)。
文摘In the pursuit of sustainable energy solutions,the efficiency of the hydrogen evolution reaction(HER)in alkaline conditions has been a significant challenge,primarily due to the sluggish dissociation of water molecules on platinum(Pt)catalysts.Addressing this critical issue,our study introduces an innovative Pt-Co@NCS catalyst.This catalyst synergistically combines Pt nanoparticles with Co single atoms on a nitrogen-doped carbon scaffold,overcoming the traditional bottleneck of slow water dissociation.Its unique porous concave structure and nitrogen-enriched surface not only provide abundant anchoring sites for Co atoms but also create a conducive hydrophilic environment around the Pt particles.This design leads to a drastic improvement in the water dissociation process,as demonstrated by CO stripping and deuterium labeling experiments.Achieving an outstanding current density of 162.8 mA cm^(−2) at−0.1 V versus RHE,a Tafel slope of 26.2 mV dec^(−1),and a superior nominal mass activity of 15.75 mAμgPt^(−1),the Pt-Co@NCS catalyst represents a significant step forward in enhancing alkaline HER efficiency,indicating promising advancements in the field.
基金National Natural Science Foundation of China,Grant/Award Numbers:U21A20332,52103226,52202275,52203314,12204253Distinguished Young Scholars Fund of Jiangsu Province,Grant/Award Number:BK20220061+1 种基金Fellowship of China Postdoctoral Science Foundation,Grant/Award Number:2021M702382Suzhou Foreign Academician Workstation,Grant/Award Number:SWY2022001。
文摘Carbon-free electrochemical nitrogen reduction reaction(NRR)is an appealing strategy for green ammonia synthesis,but there is still a significant performance bottleneck.Conventional working electrode is usually flooded by the electrolyte during the NRR test,and only the surface material could get access to the nitrogen,which inevitably gives rise to sluggish reaction rate.Herein,an asymmetric electrode design is proposed to tackle this challenge.An aerophilic layer is constructed on one face of the electrocatalyst-loaded electrode,while the other side maintains its original structure,aiming to achieve facilitated nitrogen transfer and electrolyte permeation within the conductive skeleton simultaneously.This asymmetric architecture affords extensive threephase reaction region within the electrode as demonstrated by the combination of theoretical simulations and experimental measurements,which gives full play to the loaded electrocatalyst.As expected,the proofof-concept asymmetric electrode delivers an NH_(3)yield rate of 40.81μg h^(−1)mg^(−1)and a Faradaic efficiency of 71.71%at−0.3 V versus the reversible hydrogen electrode,which are more than 4 and 7 times that of conventional electrode,respectively.This work presents a versatile strategy for enhancing the interfacial reaction kinetics and is instructive to electrode design for gas-involved electrochemical reactions.
基金supported by the National Natural Science Foundation of China(NSFC,21733004,22002088)the INTERNATIONAL COOPERATION Program of Shanghai Science and Technology Committee(STCSM,17520711200)+1 种基金the Shanghai Sailing Program(20YF1420500)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2020MS007).
文摘Electrochemical energy storage and conversion toward sustainable carbon neutrality cycle is of great interest in today's society.In this perspective,we highlight the interconversion between carbon dioxide and formic acid by means of electrocatalytic CO_(2)reduction reaction(CO_(2)RR)and formic acid oxidation reaction(FAOR)as an effective way to achieve that goal.In line with the distinctive catalytic nature of Pd to reversibly drive both FAOR and CO_(2)RR,we first illustrate the intimate mechanistic relation between these two reversed reactions over Pd surfaces.Next,recent advances in developing Pd-based bifunctional catalysts and relevant optimization strategies are briefly summarized,including geometric structure engineering with preferential facet exposure,construction of crystallographic ordering intermetallic,electronic structure manipulation through metal or metalloid doping to fine tune the binding strength for active and poisoning intermediates.At the end,our viewpoints on the design principles at both microscopic and macroscopic scales are offered toward an efficient CO_(2)and HCOOH interconversion loop.
