As a result of the agglomeration of layered double-metal hydrox-ides (LDHs), their electrocatalytic activity of oxygen evolution reac-tion (OER) is usually suppressed. Herein, we propose simple co -pre-cipitation and surface etching for the preparation of ordered macroporous-mesoporous CoNiFe-LDHs with high-density defects. The ordered structure avoids the agglomeration of single-layer nanosheets. Meanwhile, the high-density defects on the nanosheet surface generate abundant metal vacancies and oxygen vacancies, distorting the single-layer nanosheets significantly and altering the electronic properties around the metal (M)-M and M-O bonds, which enhances the adsorption of intermediates and accelerates the rate-controlling reaction step of O*-> OOH*. This new material shows an extremely low overpotential of 197 mV at a current density of 10 mA cm -2 and a surprising stability of over 70 h in alkaline me-dia. This work provides a new synthesis protocol for hierarchical porous LDHs with excellent OER catalytic activity.
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机译:由于层状双金属羟基化物(LDHs)的团聚,其析氧反应(OER)的电催化活性通常受到抑制。本文提出了一种简单的共沉淀和表面刻蚀法,用于制备具有高密度缺陷的有序大孔-介孔CoNiFe-LDHs。有序结构避免了单层纳米片的团聚。同时,纳米片表面的高密度缺陷产生丰富的金属空位和氧空位,使单层纳米片发生显著畸形,改变金属(M)-M和M-O键周围的电子性质,增强了中间体的吸附,加速了O*->OOH*的速率控制反应步骤。这种新材料在10 mA cm -2的电流密度下显示出197 mV的极低过电位,并且在碱性介质中具有超过70小时的惊人稳定性。本工作为具有优异OER催化活性的多级多孔LDHs提供了新的合成方案。
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