Enhancement of Electrocatalytic Activity as a Function of Structural Order in Perovskite Oxides
Enhancement of Electrocatalytic Activity as a Function of Structural Order in Perovskite Oxides
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DOI：
10.1021/acscatal.2c02411
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发表时间：
2022-08-08
期刊：
影响因子：
12.9
通讯作者：
Ramezanipour, Farshid
中科院分区：
文献类型：
--
作者：
Karki, Surendra B.;Hona, Ram Krishna;Ramezanipour, Farshid
电催化裂解水是一种很有前途的制氢方法。在这里，我们报告了一种增强的水电解的电催化性能，通过逐步增加氧化物结构网络中氧空位的有序性来实现。在从Sr2FeCoO6-Delta(无序)到CaSrFeCoO6-Delta(有序)和Ca2FeCoO6-Delta(高度有序)的转变过程中，A位金属的平均离子半径的变化导致氧空位的浓度和有序性增加，导致水分解的阴极和阳极半反应，即析氢(HER)和析氧(OER)反应的电催化活性逐渐增强。由于OER电催化被认为是电解水的瓶颈，因此OER电催化尤为重要。这些电催化剂表现出比贵金属催化剂RuO2更好的活性。与迄今报道的大多数双功能催化剂不同，这些催化剂可以批量使用，不需要纳米制造、复合形成或任何额外处理。密度泛函理论计算表明，空位有序导致电子能带向费米能级方向移动。我们认为氧空位的有序性可以作为设计高活性电催化剂的一种手段。
Electrocatalytic splitting of water is a promising method of hydrogen generation. Here, we report an enhanced electrocatalytic performance for water electrolysis, achieved through a progressive increase in the ordering of oxygen vacancies in the structural network of oxides. In transition from Sr2FeCoO6-delta (disordered) to CaSrFeCoO6-delta (ordered) and Ca2FeCoO6-delta (highly ordered), the change in the average ionic radius of the A-site metals leads to an increase in the concentration and ordering of oxygen vacancies, resulting in a progressive enhancement of the electrocatalytic activity for both cathodic and anodic half-reactions of water splitting, i.e., hydrogen-evolution (HER) and oxygen-evolution (OER) reactions. The OER electrocatalysis is particularly important, as it is considered the bottleneck for water electrolysis. These electrocatalysts show better activity than the precious metal catalyst RuO2. In contrast to most bifunctional catalysts reported to date, these catalysts can be used in bulk form, without the need for nanofabrication, composite formation, or any additional processing. Density functional theory calculations indicate that the vacancy order leads to a shift of the electronic bands toward the Fermi level. We propose that the ordering of oxygen vacancies can be used as a handle for the design of highly active electrocatalysts.