Abstract Perovskite oxide is a potential alternative to precious metal oxides like IrO2 and RuO2 as electrocatalysts in the oxygen evolution reaction (OER), mostly for its cost-effectiveness and adequate stability. However, the low catalytic activity in the OER limits its practical application. This paper deals with the preparation of perovskite oxides (by the sol-gel method) with enhanced electrocatalytic activity through selective dissolution of A-site cations of La0.6Sr0.4Co0.8Fe0.2O3 (LSCF) in order to tune the A-site cation deficiency. Additionally, a thorough investigation of the catalysts’ OER performance was performed in a 0.1 mol⋅L−1 KOH solution. Based on the results of XRD, SEM, TEM, XPS and ICP-AES, it can be concluded that selective dissolution of Sr cations on A-sites can be achieved using a HNO3 etching remaining the perovskite structure. The OER catalytic activity of LSCF can be effectively promoted after acid etching for 6 h, which can be attributed to the higher surface area (BET result) and ratio of the high oxidative oxygen species (O2−/O−) and surface oxygen species (OH−/O2). Moreover, the LSCF catalysts maintains an appropriate electrochemical stability after acid etching. Our work offers a simple but effective way to modify the perovskite surface so as to boost the OER performance.

中文翻译：

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选择性溶解 La0.6Sr0.4Co0.8Fe0.2O3 钙钛矿催化剂的 A 位阳离子以增强析氧反应

摘要 钙钛矿氧化物是 IrO2 和 RuO2 等贵金属氧化物作为析氧反应 (OER) 电催化剂的潜在替代品，主要是因为其具有成本效益和足够的稳定性。然而，OER中的低催化活性限制了其实际应用。本文通过选择性溶解 La0.6Sr0.4Co0.8Fe0.2O3 (LSCF) 的 A 位阳离子来调节 A 位，从而制备具有增强电催化活性的钙钛矿氧化物（通过溶胶-凝胶法）。阳离子缺乏。此外，在 0.1 mol·L-1 KOH 溶液中对催化剂的 OER 性能进行了彻底研究。基于 XRD、SEM、TEM、XPS 和 ICP-AES 的结果，可以得出结论，使用 HNO3 蚀刻保留钙钛矿结构可以实现 Sr 阳离子在 A 位上的选择性溶解。LSCF 的 OER 催化活性在酸蚀刻 6 h 后可以得到有效提升，这可以归因于更高的表面积（BET 结果）和高氧化氧物种（O2-/O-）与表面氧物种（ OH-/O2)。此外，LSCF催化剂在酸蚀刻后保持适当的电化学稳定性。我们的工作提供了一种简单但有效的方法来修改钙钛矿表面以提高 OER 性能。此外，LSCF催化剂在酸蚀刻后保持适当的电化学稳定性。我们的工作提供了一种简单但有效的方法来修改钙钛矿表面以提高 OER 性能。此外，LSCF催化剂在酸蚀刻后保持适当的电化学稳定性。我们的工作提供了一种简单但有效的方法来修改钙钛矿表面以提高 OER 性能。