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氧进化反应的兰促进电催化剂:独特的催化剂或氧化物解构?

Alaina C Hartnett¹, Ryan J Evenson¹, Agnes E Thorarinsdottir¹

¹Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.

Journal of the American Chemical Society

|December 20, 2024

概括

在氧化物 (Co3O4) 电催化剂中加入兰,通过促进晶格解构和形成更活跃的位点来增强氧化演化反应 (OER) 的活性,而不是改善内在催化.

科学领域:

材料科学
电化学
催化剂

背景情况:

常规氧演化反应 (OER) 催化剂的评估依赖于当前密度在设置过量的潜力.
这一指标对于OER催化剂是不可靠的,因为格子解构和无形化在工作条件下增加了活性位点.

研究的目的:

研究 (La3+) 加入氧化物 (Co3O4) 对OER性能的影响.
在OER催化过程中阐明La-改性CO3O4的结构和化学变化.

主要方法:

用粉末X射线衍射 (PXRD),拉曼光谱和扩展X射线吸收细结构 (EXAFS) 来分析材料结构.
操作光谱和高分辨率传输电子显微镜 (HRTEM) 用于在OER条件下研究催化剂的行为.
在催化后测定表面化学状态的X射线光电谱 (XPS).

主要成果:

加入到CO3O4导致域大小减少,远程顺序减少和无形化增加.
在OER条件下,La3+加速了格子的解构,形成了一个无形的上层.
随着La3+度的增加,OER过量降低,达到17%的La合.
后OERXPS显示了格子氧化物的损失和化/缺陷的Co (O) (OH) 物种的形成.

结论:

在Lad-doped Co3O4中改善的OER活性是由于格子解构和形成更活跃的Co ((O)) ((OH)) 边缘位点.
增强的性能源于增加的活性位点数,而不是改善的内在催化性能.
这种机制可能适用于氧化物催化剂中的其他金属离子剂.

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