Achieving delafossite analog by in situ electrochemical self-reconstruction as an oxygen-evolving catalyst
Achieving delafossite analog by in situ electrochemical self-reconstruction as an oxygen-evolving catalyst
复制标题
通过原位电化学自重构作为析氧催化剂实现铜铁矿类似物
DOI：
10.1073/pnas.2009180117
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发表时间：
2020-09-08
影响因子：
11.1
通讯作者：
Guo, Lin
中科院分区：
文献类型：
--
作者：
Liu, Juzhe;Hu, Qi;Guo, Lin
Significance Electrochemical water splitting to generate hydrogen and oxygen is proposed as a promising way for building a clean-energy future. One of the challenges facing this scenario is to develop robust electrocatalysts, especially for the kinetically sluggish oxygen evolution reaction (OER) process. In this work, the delafossite analog was proposed by mutation of metal oxyhydroxides and delafossite. We have experimentally realized the delafossite analog by intercalation of Ag into cobalt–iron (oxyhydr)oxide layers via electrochemical self-reconstruction (ECSR). The delafossite analog exhibits enhanced OER activity and outstanding stability. Our findings demonstrate that in situ ECSR can be an effective approach to construct new types of catalysts. Our advances on delafossite analogs pave the vital way for a class of promising electrochemical catalysts. Development of novel and robust oxygen evolution reaction (OER) catalysts with well-modulated atomic and electronic structure remains a challenge. Compared to the well-known metal hydroxides or (oxyhydr)oxides with lamellar structure, delafossites (ABO2) are characterized by alternating layers of A cations and edge-sharing BO2 octahedra, but are rarely used in OER due to their poor electron conductivity and intrinsic activity. Here, we propose a delafossite analog by mutation of metal oxyhydroxide and delafossite based on first-principles calculations. Modulation on the electronic structure due to distortion of the original crystal field of the BO2 layers is calculated to enhance electron conductivity and catalytic activity. Inspired by the theoretical design, we have experimentally realized the delafossite analog by electrochemical self-reconstruction (ECSR). Operando X-ray absorption spectroscopy and other experimental techniques reveal the formation of delafossite analog with Ag intercalated into bimetallic cobalt–iron (oxyhydr)oxide layers from a metastable precursor through amorphization. Benefitting from the featured local electronic and geometric structures, the delafossite analog shows superior OER activity, affording a current density of 10 mA⋅cm−2 at an overpotential of 187 mV and an excellent stability (300 h) in alkaline conditions.
