In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion redu...In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.展开更多
Electrocarboxylation of carbon dioxide(CO_(2))using organic substrates has emerged as a promising method for the sustainable synthesis of value-added carboxylic acids due to its renewable energy source and mild reacti...Electrocarboxylation of carbon dioxide(CO_(2))using organic substrates has emerged as a promising method for the sustainable synthesis of value-added carboxylic acids due to its renewable energy source and mild reaction conditions.The reactivity and product selectivity of electrocarboxylation are highly dependent on the cathodic behavior,involving a sequence of electron transfers and chemical reactions.Hence,it is necessary to understand the cathodic reaction mechanisms for optimizing reaction performance and product distribution.In this work,a review of recent advancements in the electrocarboxylation of CO_(2)with organic substrates based on different cathodic reaction pathways is presented to provide a reference for the development of novel methodologies of CO_(2)electrocarboxylation.Herein,cathodic reactions are particularly classified into two categories based on the initial electron carriers(i.e.,CO_(2)radical anion and substrate radical anion).Furthermore,three cathodic pathways(ENE(N),ENED,and EDEN)of substrate radical anion-induced electrocarboxylation are discussed,which differ in their electron transfer sequence,substrate dissociation,and nucleophilic reaction,to highlight their implications on reactivity and product selectivity.展开更多
Pt-based materials are the benchmarked catalysts in the cathodic hydrogen evolution reaction(HER)of water splitting;the prohibitive cost and scarcity of Pt immensely impede the commercialization of hydrogen energy.Ru ...Pt-based materials are the benchmarked catalysts in the cathodic hydrogen evolution reaction(HER)of water splitting;the prohibitive cost and scarcity of Pt immensely impede the commercialization of hydrogen energy.Ru has aroused significant concern because of its Pt-like activity and much lower price.However,it’s still a top priority to minimize the Ru loading and pursue the most superior cost performance.展开更多
Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affect...Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affecting ORR of magnesium(Mg)alloys are still unclear,especially in cases under thin elec-trolyte layers(TEL).In this work,the influence of the corrosion product films on the cathodic reactions of Mg alloys under TEL and in a bulk solution was investigated.ORR does not influence the hydrogen evolution rates in the corrosion of Mg alloys.Therefore,with the existence of oxygen,corrosion rates of Mg alloys measured by hydrogen evolution tests are not accurate under TEL.And weight loss test is a more accurate method to evaluate Mg corrosion rates under TEL.ORR was confirmed to participate in the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys under TEL.In 100-μm TEL,the highest con-tribution of ORR in cathodic reactions for the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys are 28.6%,39.1%,and 35.8%,respectively.The more protective film on Mg-4Nd-0.4Zr alloy provides a stronger inhibition effect against the diffusion of oxygen,leading to decreased ORR contribution in ca-thodic reactions.In addition,it is suggested that the preparation of Mg alloys with protective corrosion product films can inhibit the corrosion induced by ORR in the atmosphere.This work emphasizes the effects of corrosion product films on ORR in Mg corrosion,especially under TEL.展开更多
Understanding the mechanisms of oxygen anion electrochemical reactions within crystals has long perplexed electrochemical scientists and hindered the structural design and composition optimization of Li-ion cathode ma...Understanding the mechanisms of oxygen anion electrochemical reactions within crystals has long perplexed electrochemical scientists and hindered the structural design and composition optimization of Li-ion cathode materials.Machine learning interatomic potentials(MLIP)are transforming the landscape by enabling high-accuracy atomistic modeling on a large scale in materials science and chemistry.The diversity and comprehensiveness of the dataset are fundamental to building a high-accuracy MLIP.Here,we constructed a Li_(1.2–x)Mn_(0.6)Ni_(0.2O_(2))(x=0–1.04)dataset that includes over 15,000 chemical non-equilibrium and chemical equilibrium structures.Using this dataset,we trained an MLIP model(multistate equilibrium potential,named MSEP)with test accuracies of 0.008 eV/atom and 0.153 eV/Åfor energy and force,respectively.Through MSEP-MD simulations,we identify a kinetically viable O-redox mechanism in which the formation of transient interlayer O_(2)^(2−),O_(2)^(−)or O_(3)^(−)intermediates drives out-of-plane Mn and Ni migration,resulting in O_(2)molecules forming within the bulk structure.O3−intermediates have a certain ability to capture O_(2),which may help alleviate the formation of lattice O_(2).展开更多
The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it st...The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it still remains a challenge how to integrate these beneficial physical and chemical properties to promote the electrocatalytic performances for anode and cathode reactions in fuel cells.Herein,highly catalytic Pt_(n)Cu_(100−n)catalysts with many active sites were synthesized through optimizing the compositions of precursors and reaction conditions and a surfactant-free thermal solvent method,which showed a subtle lattice strain.Transmission electron microscopy and X-ray diffraction results revealed that the lattice strain of Pt_(n)Cu_(100−n)alloy nanostellates could be modulated by the alloy compositions.Electrochemical results showed that the high catalytic activity of Pt_(n)Cu_(100−n)alloy nanostellate catalysts for both the oxygen reduction and alcohol oxidation reactions was related to lattice shrinkage,facets and bimetallic compositions.Interestingly,Pt_(69)Cu_(31)/C nanostellate catalysts with lattice shrinking revealed the maximum activity and stability compared with other compositions and commercial Pt/C,which was also supported by DFT results.This study will provide a new path for the design of robust and active nanoalloy catalysts with lattice mismatch and dominant active facets for both the cathode and anode reactions in fuel cells.展开更多
The use of metal-free carbon nanomaterials as cathodic oxygen reduction reaction(ORR)catalysts has rapidly grown due to their low cost,high electrical conductivity,and great stability.Recent progress has demonstrated ...The use of metal-free carbon nanomaterials as cathodic oxygen reduction reaction(ORR)catalysts has rapidly grown due to their low cost,high electrical conductivity,and great stability.Recent progress has demonstrated that defective carbons co-doped with heteroatoms(e.g.N and S)usually have high activity.However,the role and contribution of the inherent defects and these dopants towards the ORR performance are still unambiguous.Herein,we have stepwise manipulated the heteroatom(N and S)doping,conversion and removal on carbon defects,combined with electrocatalytic performance evaluation,and systematically investigated the synergistic effect between the heteroatoms and carbon defects.The experimental results demonstrated that pyridinic-and pyrrolic-N atoms are more important than graphitic-N atoms for obtaining high ORR activity of the ORR catalyst and they could be considered as active N doping atoms.The synergistic effect of the active N doping atoms and defects is crucial for high ORR activity of the carbon catalyst.Without the active N species,only S doping provides a limited contribution for improving the catalysis performance of defective carbon.However,the S and active N co-doping on defective carbon could boost the acidic ORR performance of the catalyst with a high half-wave potential of 0.77 V in 0.1 M HClO_(4),which is superior to that of most metal-free electrocatalysts reported to date.This work provides an example of studying the catalytic contribution of multiple active centres from the perspective of synthesis control.展开更多
Nitrate-methanol co-electrolysis involving the cathodic nitrate reduction reaction(NO_(3)RR)combined with the anodic methanol oxidation reaction(MOR)is a viable way to synchronously produce ammonia(NH_(3))and formate ...Nitrate-methanol co-electrolysis involving the cathodic nitrate reduction reaction(NO_(3)RR)combined with the anodic methanol oxidation reaction(MOR)is a viable way to synchronously produce ammonia(NH_(3))and formate via gentle,sustainable and energy-saving“E-refining”and“E-reforming”means.An efficient bifunctional catalyst for the NO_(3)RR and MOR is pivotal to achieve such a goal.In this work,a nitrogen-doped carbon-encapsulated nickel iron phosphide hybrid(Ni_(2)FeP@NC)was prepared as a bifunctional catalyst for the NO_(3)RR and MOR,and its electrochemical performance for nitrate-methanol co-electrolysis was investigated.The Ni_(2)FeP@NC catalyst exhibited a high NH_(3) yield(0.47 mmol h^(-1) cm^(-2) at-0.35 V)and faradaic efficiency(FE,93%at-0.15 V)for the NO_(3)RR and simultaneously demonstrated high MOR efficiency for formate production(yield of 1.62 mmol h^(-1) cm^(-2) at 1.7 V and FE of around 95%).The bifunctional catalytic features of the nitrate-methanol co-electrolysis system enabled the concurrent production of NH_(3) and formate at low input voltage.This work provides a viable paradigm for pairwise electrosynthesis of valuable chemicals via“E-refining”and“E-reforming”through the rational design of bifunctional catalysts.展开更多
Metal–air batteries are an appealing option for energy storage,boasting a high energy density and environmental sustainability.Researchers focus on the catalyst design to solve the problem of sluggish cathode reactio...Metal–air batteries are an appealing option for energy storage,boasting a high energy density and environmental sustainability.Researchers focus on the catalyst design to solve the problem of sluggish cathode reaction kinetic.However,in some cases,where thermodynamic regulation is required,the role of catalysts is limited.Based on catalysts changing reaction kinetics,external fields can change the thermodynamic parameters of the reaction,further reduce overpotential,and accelerate the reaction rate.By selecting appropriate external fields and adjusting controllable variables,greater flexibility and potential are provided for reaction control.This paper reviews the basic principles by which several external fields influence metal–air batteries.Additionally,some design strategies of photoelectrode materials,the similarities and differences of different magnetic field effects,and some research progress of the ultrasonic field,stress field,and microwave field are systematically summarized.Multifield coupling can also interact and produce additive effects.Furthermore,introducing external fields will also bring about the problem of aggravated side reactions.This paper proposes some research methods to explore the specific reaction mechanism of external field assistance in more depth.The primary objective is to furnish theoretical direction for enhancing the performance of external field-supported metal–air batteries,thereby advancing their development.展开更多
基金supported by the National Key Research and Development Program(No.2022YFC2806200)the National Key Research and Development Program(No.2023YFC2810800)the Natural Science Foundation of China(No.52001055).
文摘In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.
基金received from the National Natural Science Foundation of China(No.22278305)National Key R&D Program of China(2022YFB4101900)。
文摘Electrocarboxylation of carbon dioxide(CO_(2))using organic substrates has emerged as a promising method for the sustainable synthesis of value-added carboxylic acids due to its renewable energy source and mild reaction conditions.The reactivity and product selectivity of electrocarboxylation are highly dependent on the cathodic behavior,involving a sequence of electron transfers and chemical reactions.Hence,it is necessary to understand the cathodic reaction mechanisms for optimizing reaction performance and product distribution.In this work,a review of recent advancements in the electrocarboxylation of CO_(2)with organic substrates based on different cathodic reaction pathways is presented to provide a reference for the development of novel methodologies of CO_(2)electrocarboxylation.Herein,cathodic reactions are particularly classified into two categories based on the initial electron carriers(i.e.,CO_(2)radical anion and substrate radical anion).Furthermore,three cathodic pathways(ENE(N),ENED,and EDEN)of substrate radical anion-induced electrocarboxylation are discussed,which differ in their electron transfer sequence,substrate dissociation,and nucleophilic reaction,to highlight their implications on reactivity and product selectivity.
基金supported by the Development Project of Youth Innovation Team in Shandong Colleges and Universities(No.2019KJC031)the Natural Science Foundation of Shandong Province(Nos.ZR2019MB064,ZR2021MB122 and ZR2022MB137)the Doctoral Program of Liaocheng University(No.318051608).
文摘Pt-based materials are the benchmarked catalysts in the cathodic hydrogen evolution reaction(HER)of water splitting;the prohibitive cost and scarcity of Pt immensely impede the commercialization of hydrogen energy.Ru has aroused significant concern because of its Pt-like activity and much lower price.However,it’s still a top priority to minimize the Ru loading and pursue the most superior cost performance.
基金supported by the National Natu-ral Science Foundation of China(Nos.U23A20555 and 52271008)the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)the Joint Research Fund of Advanced Technology by Shanghai Aerospace(No.USCAST2023-15).
文摘Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affecting ORR of magnesium(Mg)alloys are still unclear,especially in cases under thin elec-trolyte layers(TEL).In this work,the influence of the corrosion product films on the cathodic reactions of Mg alloys under TEL and in a bulk solution was investigated.ORR does not influence the hydrogen evolution rates in the corrosion of Mg alloys.Therefore,with the existence of oxygen,corrosion rates of Mg alloys measured by hydrogen evolution tests are not accurate under TEL.And weight loss test is a more accurate method to evaluate Mg corrosion rates under TEL.ORR was confirmed to participate in the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys under TEL.In 100-μm TEL,the highest con-tribution of ORR in cathodic reactions for the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys are 28.6%,39.1%,and 35.8%,respectively.The more protective film on Mg-4Nd-0.4Zr alloy provides a stronger inhibition effect against the diffusion of oxygen,leading to decreased ORR contribution in ca-thodic reactions.In addition,it is suggested that the preparation of Mg alloys with protective corrosion product films can inhibit the corrosion induced by ORR in the atmosphere.This work emphasizes the effects of corrosion product films on ORR in Mg corrosion,especially under TEL.
基金supported by the National Key R&D Program of China(2022YFB3807200)the National Natural Science Foundation of China,NSFC(22133005,22403103)+2 种基金the Project funded by China Postdoctoral Science Foundation(2022M723276 and GZB20230793)Sponsored by the Shanghai Sailing Program(23YF1454900)and the Shanghai Post-doctoral Excellence Program(2022660).
文摘Understanding the mechanisms of oxygen anion electrochemical reactions within crystals has long perplexed electrochemical scientists and hindered the structural design and composition optimization of Li-ion cathode materials.Machine learning interatomic potentials(MLIP)are transforming the landscape by enabling high-accuracy atomistic modeling on a large scale in materials science and chemistry.The diversity and comprehensiveness of the dataset are fundamental to building a high-accuracy MLIP.Here,we constructed a Li_(1.2–x)Mn_(0.6)Ni_(0.2O_(2))(x=0–1.04)dataset that includes over 15,000 chemical non-equilibrium and chemical equilibrium structures.Using this dataset,we trained an MLIP model(multistate equilibrium potential,named MSEP)with test accuracies of 0.008 eV/atom and 0.153 eV/Åfor energy and force,respectively.Through MSEP-MD simulations,we identify a kinetically viable O-redox mechanism in which the formation of transient interlayer O_(2)^(2−),O_(2)^(−)or O_(3)^(−)intermediates drives out-of-plane Mn and Ni migration,resulting in O_(2)molecules forming within the bulk structure.O3−intermediates have a certain ability to capture O_(2),which may help alleviate the formation of lattice O_(2).
基金supported by the 111 Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2018003)+2 种基金the National Science Foundation of China(Grant No.21908045,51922008 and 51872075)the China Postdoctoral Science Foundation(Grant No.2018M642754)the Talent postdoctoral program for Henan province(Grant No.ZYQR201810170).
文摘The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it still remains a challenge how to integrate these beneficial physical and chemical properties to promote the electrocatalytic performances for anode and cathode reactions in fuel cells.Herein,highly catalytic Pt_(n)Cu_(100−n)catalysts with many active sites were synthesized through optimizing the compositions of precursors and reaction conditions and a surfactant-free thermal solvent method,which showed a subtle lattice strain.Transmission electron microscopy and X-ray diffraction results revealed that the lattice strain of Pt_(n)Cu_(100−n)alloy nanostellates could be modulated by the alloy compositions.Electrochemical results showed that the high catalytic activity of Pt_(n)Cu_(100−n)alloy nanostellate catalysts for both the oxygen reduction and alcohol oxidation reactions was related to lattice shrinkage,facets and bimetallic compositions.Interestingly,Pt_(69)Cu_(31)/C nanostellate catalysts with lattice shrinking revealed the maximum activity and stability compared with other compositions and commercial Pt/C,which was also supported by DFT results.This study will provide a new path for the design of robust and active nanoalloy catalysts with lattice mismatch and dominant active facets for both the cathode and anode reactions in fuel cells.
基金supported by the NSFC of China(21571139,22035003,22001132 and 22271217).
文摘The use of metal-free carbon nanomaterials as cathodic oxygen reduction reaction(ORR)catalysts has rapidly grown due to their low cost,high electrical conductivity,and great stability.Recent progress has demonstrated that defective carbons co-doped with heteroatoms(e.g.N and S)usually have high activity.However,the role and contribution of the inherent defects and these dopants towards the ORR performance are still unambiguous.Herein,we have stepwise manipulated the heteroatom(N and S)doping,conversion and removal on carbon defects,combined with electrocatalytic performance evaluation,and systematically investigated the synergistic effect between the heteroatoms and carbon defects.The experimental results demonstrated that pyridinic-and pyrrolic-N atoms are more important than graphitic-N atoms for obtaining high ORR activity of the ORR catalyst and they could be considered as active N doping atoms.The synergistic effect of the active N doping atoms and defects is crucial for high ORR activity of the carbon catalyst.Without the active N species,only S doping provides a limited contribution for improving the catalysis performance of defective carbon.However,the S and active N co-doping on defective carbon could boost the acidic ORR performance of the catalyst with a high half-wave potential of 0.77 V in 0.1 M HClO_(4),which is superior to that of most metal-free electrocatalysts reported to date.This work provides an example of studying the catalytic contribution of multiple active centres from the perspective of synthesis control.
基金supported by NSFC(No.51802084)the 111 Project(No.D17007)Henan Center for Outstanding Oversea Scientists(No.GZS_(2)022017).
文摘Nitrate-methanol co-electrolysis involving the cathodic nitrate reduction reaction(NO_(3)RR)combined with the anodic methanol oxidation reaction(MOR)is a viable way to synchronously produce ammonia(NH_(3))and formate via gentle,sustainable and energy-saving“E-refining”and“E-reforming”means.An efficient bifunctional catalyst for the NO_(3)RR and MOR is pivotal to achieve such a goal.In this work,a nitrogen-doped carbon-encapsulated nickel iron phosphide hybrid(Ni_(2)FeP@NC)was prepared as a bifunctional catalyst for the NO_(3)RR and MOR,and its electrochemical performance for nitrate-methanol co-electrolysis was investigated.The Ni_(2)FeP@NC catalyst exhibited a high NH_(3) yield(0.47 mmol h^(-1) cm^(-2) at-0.35 V)and faradaic efficiency(FE,93%at-0.15 V)for the NO_(3)RR and simultaneously demonstrated high MOR efficiency for formate production(yield of 1.62 mmol h^(-1) cm^(-2) at 1.7 V and FE of around 95%).The bifunctional catalytic features of the nitrate-methanol co-electrolysis system enabled the concurrent production of NH_(3) and formate at low input voltage.This work provides a viable paradigm for pairwise electrosynthesis of valuable chemicals via“E-refining”and“E-reforming”through the rational design of bifunctional catalysts.
基金funded by the National Key R&D Program of China(2021YFB2012500)supported by the National Natural Science Foundation of China(No.52273081,No.52433002)the Young Talent Support Plan of Xi’an Jiaotong University.
文摘Metal–air batteries are an appealing option for energy storage,boasting a high energy density and environmental sustainability.Researchers focus on the catalyst design to solve the problem of sluggish cathode reaction kinetic.However,in some cases,where thermodynamic regulation is required,the role of catalysts is limited.Based on catalysts changing reaction kinetics,external fields can change the thermodynamic parameters of the reaction,further reduce overpotential,and accelerate the reaction rate.By selecting appropriate external fields and adjusting controllable variables,greater flexibility and potential are provided for reaction control.This paper reviews the basic principles by which several external fields influence metal–air batteries.Additionally,some design strategies of photoelectrode materials,the similarities and differences of different magnetic field effects,and some research progress of the ultrasonic field,stress field,and microwave field are systematically summarized.Multifield coupling can also interact and produce additive effects.Furthermore,introducing external fields will also bring about the problem of aggravated side reactions.This paper proposes some research methods to explore the specific reaction mechanism of external field assistance in more depth.The primary objective is to furnish theoretical direction for enhancing the performance of external field-supported metal–air batteries,thereby advancing their development.
