Healing the structural defects of spinel MnFe_(2)O_(4) to enhance the electrocatalytic activity for oxygen reduction reaction  

作　　者：Manting Tang Yue Zou Zhiyong Jiang Peiyu Ma Zhiyou Zhou Xiaodi Zhu Jun Bao Shi-Gang Sun 

机构地区：[1]National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230026,Anhui,China [2]State Key Laboratory of Physical Chemistry of Solid Surfaces,Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 36005 Fujian,China [3]iChEM(Collaborative Innovation Center of Chemistry for Energy Materials),University of Science and Technology of China,Hefei 230026,Anhui,China

出　　处：《Journal of Energy Chemistry》2024年第10期12-19,I0001,共9页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China (12241502,52002367);the Fundamental Research Funds for the Central Universities (20720220010);the National Key Research and Development Program of China (2019YFA0405602)。

摘　　要：Spinel metal oxides containing Mn,Co,or Fe(AB_(2)O_(4),A/B=Mn/Fe/Co)are one of the most promising nonPt electrocatalysts for oxygen reduction reaction(ORR)in alkaline conditions.However,the low conductivity of metal oxides and the poor intrinsic activities of transition metal sites lead to unsatisfactory ORR performance.In this study,eutectic molten salt(EMS)treatment is employed to reconstruct the atomic arrangement of MnFe_(2)O_(4)electrocatalyst as a prototype for enhancing ORR performance.Comprehensive analyses by using XAFS,soft XAS,XPS,and electrochemical methods reveal that the EMS treatment reduces the oxygen vacancies and spinel inverse in MnFe_(2)O_(4)effectively,which improves the electric conductivity and increases the population of more catalytically active Mn^(2+)sites with tetrahedral coordination.Moreover,the enhanced Mn-O interaction after EMS treatment is conducive to the adsorption and activation of O_(2),which promotes the first electron transfer step(generally considered as the ratedetermining step)of the ORR process.As a result,the EMS treated MnFe_(2)O_(4)catalyst delivers a positive shift of 40 mV in the ORR half-wave potential and a two-fold enhanced mass/specific activity.This work provides a convenient approach to manipulate the atomic architecture and local electronic structure of spinel oxides as ORR electrocatalysts and a comprehensive understanding of the structureperformance relationship from the molecular/atomic scale.

关 键 词：Spinel MnFe_(2)O_(4) Oxygen reduction reaction Spinel inverse Oxygen vacancies Eutectic molten salt 

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