电催化剂
铱
析氧
催化作用
氧化物
溶解
原子单位
分解水
电解水
材料科学
化学工程
纳米技术
化学物理
化学
电解
无机化学
电化学
物理化学
电极
冶金
工程类
物理
电解质
光催化
量子力学
生物化学
作者
Tong Li,Olga Kasian,Serhiy Cherevko,S. Zhang,Simon Geiger,Christina Scheu,Peter Felfer,Dierk Raabe,Baptiste Gault,Karl J. J. Mayrhofer
出处
期刊:Nature Catalysis
[Springer Nature]
日期:2018-03-26
卷期号:1 (4): 300-305
被引量:181
标识
DOI:10.1038/s41929-018-0043-3
摘要
The topmost atomic layers of electrocatalysts determine the mechanism and kinetics of reactions in many important industrial processes, such as water splitting, chlor-electrolysis or fuel cells. Optimizing the performance of electrocatalysts requires a detailed understanding of surface-state changes during the catalytic process, ideally at the atomic scale. Here, we use atom probe tomography to reveal the three-dimensional structure of the first few atomic layers of electrochemically grown iridium oxide, an efficient electrocatalyst for the oxygen evolution reaction. We unveil the formation of confined, non-stoichiometric Ir–O species during oxygen evolution. These species gradually transform to IrO2, providing improved stability but also a decrease in activity. Additionally, electrochemical growth of oxide in deuterated solutions allowed us to trace hydroxy-groups and water molecules present in the regions of the oxide layer that are favourable for the oxygen evolution and iridium dissolution reactions. Overall, we demonstrate how tomography with near-atomic resolution advances the understanding of complex relationships between surface structure, surface state and function in electrocatalysis. Morphological changes in catalyst structure are known to occur during electrocatalysis, and understanding such changes is important to gain insight into the catalytic process. Now, in the case of iridium oxide, these surface changes are probed in atomic-scale detail during the oxygen evolution reaction, and correlated with activity and stability.
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