尖晶石
析氧
价(化学)
表面工程
氧气
材料科学
八面体
吸附
氧化态
化学物理
无机化学
化学
化学工程
纳米技术
电化学
结晶学
晶体结构
物理化学
电极
金属
冶金
有机化学
工程类
作者
Tao Zhang,Yipu Liu,Tong Li,Jie Yu,Shiwei Lin,Yue Li,Hong Jin Fan
出处
期刊:ACS Nano
[American Chemical Society]
日期:2023-03-20
卷期号:17 (7): 6770-6780
被引量:13
标识
DOI:10.1021/acsnano.2c12810
摘要
Promoting the electron occupancy of active sites to unity is an effective method to enhance the oxygen evolution reaction (OER) performance of spinel oxides, but it remains a great challenge. Here, an in situ approach is developed to modify the valence state of octahedral Ni cations in NiFe2O4 inverse spinel via surface sulfates (SO42–). Different from previous studies, SO42– is directly anchored on the spinel surface instead of forming from uncontrolled conversion or surface reconstruction. Experiment and theoretical calculations reveal the precise adsorption sites and spatial arrangement for SO42– species. As a main promoting factor, surface SO42– effectively converts the crystal field stable Ni state (t2g6eg2) to the near-unity eg electron state (t2g6eg1). Moreover, the inevitable oxygen vacancies (Vo) further optimize the energy barrier of the potential-determining step (from OH* to O*). This co-modification strategy enhances turnover frequency-based electrocatalytic activity about two orders higher than the control sample without surface sulfates. This work may provide insight into the OER activity enhancement mechanism by the oxyanion groups.
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