钝化
覆盖层
分解水
吸收(声学)
赤铁矿
材料科学
吸收光谱法
光化学
光催化
析氧
化学工程
化学
无机化学
催化作用
图层(电子)
化学物理
纳米技术
电化学
物理化学
光学
电极
冶金
物理
工程类
复合材料
生物化学
作者
Ahmed S. M. Ismail,Iván García-Torregrosa,Jeroen C. Vollenbroek,Laura Folkertsma,Johan G. Bomer,Ties Haarman,Mahnaz Ghiasi,Meike Schellhorn,Maarten Nachtegaal,Mathieu Odijk,Albert van den Berg,Bert M. Weckhuysen,Frank M. F. de Groot
出处
期刊:ACS Catalysis
日期:2021-09-20
卷期号:11 (19): 12324-12335
被引量:19
标识
DOI:10.1021/acscatal.1c02566
摘要
The role that the α-Fe2O3/NiFeOOH interface plays in dictating the oxygen evolution reaction (OER) mechanism on hematite has been a source of intense debate for decades, but the chemical characteristics of this interface and its function are still ambiguous and subject to speculation. In this study, we employed operando X-ray absorption spectroscopy to investigate the interfacial dynamics at the α-Fe2O3/NiFeOOH interface. We uncovered the spontaneous formation of a FeOOH interfacial layer under (photo)electrochemical conditions. This FeOOH interfacial layer plays a role in the surface passivation of hematite and in accumulating the (photo)generated holes upon external potential application. This hole-accumulation process leads to the extraction of more (photo)generated holes from hematite before releasing them to NiFeOOH to carry out the water-splitting reaction, and it also explains the reason for the delay in the nickel oxidation process. Based on these observations, we propose a model where NiFeOOH acts mainly as an OER catalyst and a facilitator of holes extraction from hematite, while the interfacial FeOOH layer acts as a surface passivation and hole-accumulation overlayer.
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