High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic mat...High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.展开更多
In order to predict and control the properties of Cu-Cr-Sn-Zn alloy,a model of aging processes via an artificial neural network(ANN) method to map the non-linear relationship between parameters of aging process and th...In order to predict and control the properties of Cu-Cr-Sn-Zn alloy,a model of aging processes via an artificial neural network(ANN) method to map the non-linear relationship between parameters of aging process and the hardness and electrical conductivity properties of the Cu-Cr-Sn-Zn alloy was set up.The results show that the ANN model is a very useful and accurate tool for the property analysis and prediction of aging Cu-Cr-Sn-Zn alloy.Aged at 470-510 ℃ for 4-1 h,the optimal combinations of hardness 110-117(HV) and electrical conductivity 40.6-37.7 S/m are available respectively.展开更多
Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable f...Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable fuels and chemicals,the extensively studied oxygen evolution reaction(OER)at anode only generates O_(2),which is not a high-value product.Substituting the OER with thermodynamically more favorable biomass derivative oxidation reactions(BDORs)not only enables energy-saving electrocatalysis,but also provides value-added anode products.Recent achievements have demonstrated that non-noble electrocatalysts are promising for BDORs.Herein,we provide a comprehensive review on recent achievements in the field of electrochemical BDORs catalyzed by non-noble catalysts.We start by summarizing the electrocatalytic oxidation of different types of biomass-derived substrates,aiming to show the advantages of the electrocatalytic pathway and to introduce the state-of-the-art non-noble catalysts.The reaction mechanisms of non-noble-material-catalyzed BDORs are then summarized and classified into three types according to the acceptor of hydrogen species during the dehydrogenation of biomass derivatives.Subsequently,discussions are devoted to the strategies for promoting the performances of non-noble electrocatalysts.Finally,we propose our opinions regarding future trends and major challenges in this field.展开更多
文摘High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.
基金Project(2006AA03Z528) supported by the National High-Tech Research and Development Program of ChinaProject(102102210174) supported by the Science and Technology Research Project of Henan Province,ChinaProject(2008ZDYY005) supported by Special Fund for Important Forepart Research in Henan University of Science and Technology
文摘In order to predict and control the properties of Cu-Cr-Sn-Zn alloy,a model of aging processes via an artificial neural network(ANN) method to map the non-linear relationship between parameters of aging process and the hardness and electrical conductivity properties of the Cu-Cr-Sn-Zn alloy was set up.The results show that the ANN model is a very useful and accurate tool for the property analysis and prediction of aging Cu-Cr-Sn-Zn alloy.Aged at 470-510 ℃ for 4-1 h,the optimal combinations of hardness 110-117(HV) and electrical conductivity 40.6-37.7 S/m are available respectively.
基金supported by the National Natural Science Foundation of China (21978147 and 21935001)Haihe Laboratory of Sustainable Chemical Transformationssupported by the Shuimu Tsinghua Scholar Program (2021SM072)
文摘Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable fuels and chemicals,the extensively studied oxygen evolution reaction(OER)at anode only generates O_(2),which is not a high-value product.Substituting the OER with thermodynamically more favorable biomass derivative oxidation reactions(BDORs)not only enables energy-saving electrocatalysis,but also provides value-added anode products.Recent achievements have demonstrated that non-noble electrocatalysts are promising for BDORs.Herein,we provide a comprehensive review on recent achievements in the field of electrochemical BDORs catalyzed by non-noble catalysts.We start by summarizing the electrocatalytic oxidation of different types of biomass-derived substrates,aiming to show the advantages of the electrocatalytic pathway and to introduce the state-of-the-art non-noble catalysts.The reaction mechanisms of non-noble-material-catalyzed BDORs are then summarized and classified into three types according to the acceptor of hydrogen species during the dehydrogenation of biomass derivatives.Subsequently,discussions are devoted to the strategies for promoting the performances of non-noble electrocatalysts.Finally,we propose our opinions regarding future trends and major challenges in this field.
