Hypervelocity kinetics blocks harmful intermediates to enhance stability of Fe-N-C catalysts  

超快动力学阻断有害中间物种提升Fe-N-C催化剂稳定性

作　　者：Zhenyang Xie Chunyan Zhang Zhuoyang Xie Zude Shen Linsen Liu Li Li Wei Ding Zidong Wei 谢镇阳;张春燕;谢卓洋;沈组德;刘林森;李莉;丁炜;魏子栋

机构地区：[1]College of Chemistry and Chemical Engineering,State Key Laboratory of Advanced Chemical Power Sources,Center of Advanced Electrochemical Energy(CAEE),Institute of Advanced Interdisciplinary Studies,Chongqing University,Chongqing 400044,China

出　　处：《Science China Materials》2025年第3期812-819,共8页中国科学(材料科学)(英文版)

基　　金：financially supported by the National Key Research and Development Program of China(2021YFA1502000);the National Natural Science Foundation of China(22022502 and 22179012);Natural Science Foundation of Chongqing,China(CSTB2023NSCQLZX0084).

摘　　要：Hydrogen peroxide that is produced through the two-electron pathway during the catalysis of oxygen reduction reaction(ORR)is recognized as harmful to the stability of nitrogen-doped carbon and Fe-based nonprecious catalyst(Fe-N-C)for fuel cell application.A major remaining scientific question is how fast the removal of these deleterious intermediates can contribute to stability enhancement.Here,we report that the stability of Fe-N-C catalysts is positively correlated with the kinetic constant of hydrogen peroxide decomposition.Modulation of the H_(2)O_(2) decomposition kinetics by applying the frequency factor of the Arrhenius equation from 800 to 30000 s^(-1) for TiO_(2),CeO_(2) and ZrO_(2) reduced the decay rate of Fe-N-C catalysts from 0.151% to ‒0.1% in a 100-hour stability test.Fe-N-C/ZrO_(2) with a frequency factor of 30000 s^(-1) showed a 10% increase in current density during a 100-hour stability test and almost no decay during 15 hours of continuous fuel cell operation at a high potential of 0.7 V.氧还原反应过程中双电子途径产生的过氧化氢(H_(2)O_(2))对N-C和Fe-N-C催化剂在燃料电池的稳定性运行不利.其中,关键科学问题在于:如何快速去除这些有害的中间物种,从而提高稳定性.在此,我们报道了Fe-N-C催化剂的稳定性与H_(2)O_(2)分解的动力学常数呈正相关.通过使用指前因子从800到30000 s^(-1)的TiO_(2)、CeO_(2)和ZrO_(2)来调控H_(2)O_(2)分解动力学,可以发现在100小时的稳定性测试中Fe-N-C催化剂的衰减率从0.151%降至-0.1%.指前因子为30000 s^(-1)的Fe-N-C/ZrO_(2)催化剂在100小时稳定性测试中的电流密度增加了10%,其组装的阴离子交换膜燃料电池连续在0.7 V的高电位下运行15小时几乎没有衰减.

关 键 词：H_(2)O_(2)decomposition kinetics Fe-N-C stability structure-performance relationship fuel cells ORR 

分 类 号：O64[理学—物理化学]