Abstract The development of efficient non-precious metal catalysts to accelerate the oxygen evolution reaction (OER) kinetics is important for the development of water-derived hydrogen fuel. Iron-cobalt oxide ((Co, Fe)3O4) is one of the most promising transition metal-based OER electrocatalysts under alkaline conditions, but its activity is unsatisfactory due to its limited active sites and poor electronic conductivity. Herein, self-supported (Co, Fe)3O4 hierarchical nanosheet arrays with massive oxygen vacancies (denoted as VO-(Co, Fe)3O4/CC) are synthesized by a simple reduction method at room temperature. Oxygen vacancies can regulate the ratio of Co2+/Co3+, which leads to the modification of its electronic properties, and it also significantly improves the charge transfer ability and accelerates the reaction. Meanwhile, the unique hierarchical nanosheet arrays structure and abundant oxygen vacancies effectively adjust the number of OER active sites, which has a key role in developing a cost-effective oxygen electrode. Accordingly, VO-(Co, Fe)3O4/CC exhibits a relatively low overpotential of 286 mV at 10 mA cm−2 and a low Tafel slope of 41 mV dec−1.

中文翻译：

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用于高效氧气释放反应的富含缺陷的 (Co, Fe)3O4 分层纳米片阵列

摘要 开发高效的非贵金属催化剂以加速析氧反应（OER）动力学对于水衍生氢燃料的开发具有重要意义。铁钴氧化物 ((Co, Fe)3O4) 是碱性条件下最有前途的过渡金属基 OER 电催化剂之一，但由于其活性位点有限且电子导电性差，其活性并不令人满意。在此，在室温下通过简单的还原方法合成了具有大量氧空位的自支撑 (Co, Fe)3O4 分层纳米片阵列（表示为 VO-(Co, Fe)3O4/CC）。氧空位可以调节Co2+/Co3+的比值，从而改变其电子性质，同时显着提高电荷转移能力并加速反应。同时，独特的分层纳米片阵列结构和丰富的氧空位有效地调整了 OER 活性位点的数量，这对于开发具有成本效益的氧电极具有关键作用。因此，VO-(Co, Fe)3O4/CC 在 10 mA cm-2 下表现出 286 mV 的相对低过电位和 41 mV dec-1 的低塔菲尔斜率。