This study presents the engineering of a sustainable electrode for unpurified seawater electrolysis, featuring Ca-doped manganese oxide nanorods anchored on a Ni(OH)₂ microarray. The designed electrode demonstrates enhanced stability through the stabilization of Mn³⁺ species and optimized interaction, effectively mitigating the overpotential barrier of MnO_x from 310 mV to 250 mV during seawater oxidation. Ca doping induces surface oxygen vacancies, crucial for stabilizing Mn³⁺ species. The synthesized electrode exhibits distinctive characteristics, including increased surface Mn³⁺ concentration via charge state manipulation, micro and mesopores for a high specific surface area with unique hydrophilic and aerophobic properties, and strong Brønsted basicity and Lewis's acidity due to Ca doping, facilitating efficient charge transfer via effective covalent bond formation with anions. The modified catalyst demonstrated 100% faradaic efficiency for seawater electrolysis, required a low input voltage of 1.68 V to deliver a current density of 500 mA cm⁻², and sustained this performance for over 100 hours without degradation or hypochlorite formation.

中文翻译：

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稳定海水氧化中活跃的缺氧锰位点

_{本研究介绍了用于未净化海水电解的可持续电极的工程设计，其特点是锚定在 Ni(OH) 2}微阵列上的钙掺杂氧化锰纳米棒。设计的电极通过稳定 Mn ^{3+物质和优化相互作用而表现出增强的稳定性，有效地将海水氧化过程中 MnO} _x的过势垒从 310 mV 降低到 250 mV。 Ca 掺杂会引起表面氧空位，这对于稳定 Mn ³⁺物种至关重要。合成的电极表现出独特的特性，包括通过电荷态控制增加表面Mn ³⁺浓度、具有独特亲水和疏气特性的高比表面积的微孔和介孔、以及由于Ca掺杂而产生的强布朗斯台德碱性和路易斯酸性，促进高效充电通过与阴离子形成有效的共价键进行转移。改性催化剂在海水电解中表现出 100% 的法拉第效率，需要 1.68 V 的低输入电压来提供 500 mA cm ^-2的电流密度，并保持这种性能超过 100 小时而不会降解或次氯酸盐形成。