材料科学
氧气
跟踪(教育)
析氧
化学物理
化学工程
纳米技术
物理化学
电极
化学
电化学
有机化学
心理学
教育学
工程类
作者
Jinzhen Huang,Natasha Hales,Adam H. Clark,Nur Sena Yüzbasi,Camelia N. Borca,Thomas Huthwelker,Thomas J. Schmidt,Emiliana Fabbri
标识
DOI:10.1002/aenm.202303529
摘要
Abstract CeO 2 greatly enhances the electrocatalytic oxygen evolution reaction (OER) activity of CoO x , though the enhancement mechanism beyond this synergy is yet to be understood. Here, operando hard X‐ray absorption spectroscopy (hXAS) is applied to monitor the Co K edge and Ce L 3 edge in CoO x /CeO 2 to shed light on the evolution of the Co and Ce oxidation states during OER. In addition, ex situ soft XAS (sXAS) characterizations provide information on the irreversible surface‐specific transformations of the Co L 3 edge as well as of the O K edge. Combining the operando and ex situ spectroscopic characterizations with comprehensive electrochemical analyses, it is confirmed that CeO 2 is not the active center for the OER. However, coupling CeO 2 with CoO x introduces significant modifications in the Co and O species at the CoO x surface and alters the flat band potential (E fb ), leading to more favorable Co oxidation state transformations during OER and possibly modifying the preferential reaction pathway. This work establishes the connections between electronic structures, Co oxidation state and the OER reaction mechanism for CoO x /CeO 2 composites electrodes.
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