Development of an efficient, earth-abundant, inexpensive, and stable perovskite electrocatalyst to replace RuO₂ catalysts for the oxygen evolution reaction (OER) is much needed for the practical application of electrochemical energy conversion devices. Herein, we report Sm_0.5Sr_0.5Fe_0.8M_0.2O_3−δ (M = Co, Cu) perovskite doped with different transition metals at the B-site as a cheaper OER electrocatalyst in 1 M KOH electrolyte. Among the prepared catalysts, Sm_0.5Sr_0.5Fe_0.8Co_0.2O_3−δ (SSFCoO) catalysts show improved OER activity with an on-set potential of 1.48 V vs. RHE with a lower overpotential of 316 mV at 10 mA cm⁻². Furthermore, the OER performance correlated with the electronic structure of the electrocatalyst was analyzed through X-ray photoelectron spectra which revealed that the improved OER activity of the SSFCoO catalyst is due to an increased Fe⁴⁺ oxidization state. Strong Fe 3d–O 2p hybridization causes up-shifting of the O 2p valence band close to the Fermi level from 1.0 eV to 0.33 eV, significantly reducing the charge transfer energy and causing faster OH⁻ adsorption and desorption for efficient OER activity.

中文翻译：

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Sm0.5Sr0.5Fe0.8M0.2O3−δ (M = Co, Cu) 钙钛矿氧化物用于碱性电解液中的高效析氧反应

电化学能量转换装置的实际应用非常需要开发一种高效、资源丰富、价格低廉且稳定的钙钛矿电催化剂，以替代用于析氧反应 (OER) 的RuO ₂催化剂。在此，我们报告了在 B 位掺杂不同过渡金属的Sm _0.5 Sr _0.5 Fe _0.8 M _0.2 O _{3− δ} (M = Co, Cu) 钙钛矿作为 1 M KOH 电解质中更便宜的 OER 电催化剂。在制备的催化剂中，Sm _0.5 Sr _0.5 Fe _0.8 Co _0.2 O _{3− δ}(SSFCoO) 催化剂显示出改进的 OER 活性，起始电位为 1.48 V，相对于RHE，10 mA cm ^-2下的过电位为 316 mV 。此外，通过 X 射线光电子光谱分析了与电催化剂电子结构相关的 OER 性能，表明 SSFCoO 催化剂的 OER 活性提高是由于 Fe ⁴⁺氧化态的增加。强烈的 Fe 3d–O 2p 杂化导致接近费米能级的 O 2p 价带从 1.0 eV 上移到 0.33 eV，显着降低了电荷转移能并导致更快的 OH ^-吸附和解吸，以实现高效的 OER 活性。