Regulating local coordination environment of Mg-Co single atom catalyst for improved direct methanol fuel cell cathode  

作　　者：Kaiwen Wang Hanjun Zou Jiazhi Meng Chaogang Ban Xue Liu Jiangping Ma Cong Wang Liyong Gan Xiaodong Han Xiaoyuan Zhou 

机构地区：[1]College of Physics and Center of Quantum Materials and Devices,Chongqing University,Chongqing 401331,China [2]Beijing Key Laboratory of Microstructure and Property of Advanced Materials,Beijing University of Technology,Beijing 100024,China [3]Institute of Emerging Energy Storage Materials and Equipment,Chongqing 401135,China [4]Analytical and Testing Center,Chongqing University,Chongqing 401331,China

出　　处：《Journal of Magnesium and Alloys》2023年第6期1959-1969,共11页镁合金学报（英文）

基　　金：the funding support from the National Natural Science Fund for Distinguished Young Scholars(52125103);the National Natural Science Foundation of China(52071041,12074048 and 12147102);Chongqing Natural Science Foundation(cstc2020jcyj-msxm X0777 and cstc2020jcyj-msxm X0796);Science Foundation of Donghai Laboratory(DH-2022KF0307);the Fundamental Research Funds for the Central Universities(106112016CDJZR308808)。

摘　　要：Fuel cells operated with a reformate fuel such as methanol are promising power systems for portable electronic devices due to their high safety,high energy density and low pollutant emissions.However,several critical issues including methanol crossover effect,CO-tolerance electrode and efficient oxygen reduction electrocatalyst with low or non-platinum usage have to be addressed before the direct methanol fuel cells(DMFCs)become commercially available for industrial application.Here,we report a highly active and selective Mg-Co dualsite oxygen reduction reaction(ORR)single atom catalyst(SAC)with porous N-doped carbon as the substrate.The catalyst exhibits a commercial Pt/C-comparable half-wave potential of 0.806 V(versus the reversible hydrogen electrode)in acid media with good stability.Furthermore,practical DMFCs test achieves a peak power density of over 200 m W cm^(-2)that far exceeds that of commercial Pt/C counterpart(82 m W cm^(-2)).Particularly,the Mg-Co DMFC system runs over 10 h with negligible current loss under 10 M concentration methanol work condition.Experimental results and theoretical calculations reveal that the N atom coordinated by Mg and Co atom exhibits an unconventional d-band-ditto localized p-band and can promote the dissociation of the key intermediate*OOH into*O and*OH,which accounts for the near unity selective 4e-ORR reaction pathway and enhanced ORR activity.In contrast,the N atom in SAC–Co remains inert in the absorption and desorption of*OOH and*OH.This local coordination environment regulation strategy around active sites may promote rational design of high-performance and durable fuel cell cathode electrocatalysts.

关 键 词：Single atom catalyst Mg−N−Co DMFC CATHODE 

分 类 号：TM911.4[电气工程—电力电子与电力传动] TQ426[化学工程]