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Electrocatalytic enhancement mechanism of cobalt single atoms anchored on different MXene substrates in oxygen and hydrogen evolution reactions
EcoMat ( IF 10.7 ) Pub Date : 2022-10-23 , DOI: 10.1002/eom2.12293
Xin Zhao 1 , Xuerong Zheng 1, 2 , Qi Lu 2 , Ying Li 3 , Fengping Xiao 1 , Bing Tang 1 , Shixun Wang 1 , Denis Y. W. Yu 4 , Andrey L. Rogach 1
Affiliation  

Decorating single atoms of transition metals on MXenes to enhance the electrocatalytic properties of the resulting composites is a useful strategy for developing efficient electrocatalysts, and the mechanisms behind this enhancement are under intense scrutiny. Herein, we anchored Co single atoms onto several commonly used MXene substrates (V2CTx, Nb2CTx and Ti3C2Tx) and systematically studied the electrocatalytic behavior and the mechanisms of oxygen and hydrogen evolution reactions (OER and HER, respectively) of the resulting composites. Co@V2CTx composite displays an OER overpotential of 242 mV and an HER overpotential of 35 mV at 10 mA cm−2 in 1.0 M KOH electrolyte, which is much lower than for Co@Nb2CTx and Co@Ti3C2Tx, making it comparable to the commercial noble metal Pt/C and RuO2/C electrocatalysts. The experimental and theoretical results point out that the enhanced bifunctional catalytic performance of Co@V2CTx benefits from the stronger hybridization between Co 3d and surface terminated O 2p orbitals which optimized the electronic structure of Co single atoms in the composite. This, in turn, results in lowering the OER and HER energy barriers and acceleration of the catalytic kinetics in case of the Co@V2CTx composite. The advantage of Co@V2CTx was further validated by its high overall water splitting performance (1.60 V to deliver 10 mA cm−2). Our study sheds light on the origins of the catalytic activity of single transition metals atoms on MXene substrates, and provides guidelines for designing efficient bifunctional MXene-based electrocatalysts.

中文翻译:

锚定在不同 MXene 基底上的钴单原子在析氧和析氢反应中的电催化增强机制

在 MXenes 上装饰过渡金属的单个原子以增强所得复合材料的电催化性能是开发高效电催化剂的有用策略,并且这种增强背后的机制正在受到密切关注。在此,我们将 Co 单原子锚定在几种常用的 MXene 基底(V 2 CT x、Nb 2 CT x和 Ti 3 C 2 T x)上,并系统地研究了电催化行为和析氧和析氢反应(OER 和 HER)的机制,分别)所得复合材料。Co@V 2 CT x复合材料在 10 mA cm -2在 1.0 M KOH 电解质中显示出 242 mV 的 OER 过电势和 35 mV 的 HER 过电势,远低于 Co@Nb 2 CT x和 Co@Ti 3 C 2 T x,使得它可与商业贵金属Pt/C和RuO 2 /C电催化剂相媲美。实验和理论结果表明,Co@V 2 CT x增强的双功能催化性能受益于 Co 3d 和表面终止的 O 2p 轨道之间更强的杂化,优化了复合材料中 Co 单原子的电子结构。在 Co@V 2 CT x复合材料的情况下,这反过来导致降低 OER 和 HER 能垒并加速催化动力学。Co@V 2 CT x的优势通过其高整体水分解性能(1.60 V 以提供 10 mA cm -2)得到进一步验证。我们的研究阐明了单个过渡金属原子在 MXene 基底上的催化活性的起源,并为设计高效的双功能 MXene 基电催化剂提供了指导。
更新日期:2022-10-23
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