The increase in the fraction of high-valent metal cations is of significant importance for enhancing the stability of noble-metal-free catalysts in the acid oxygen evolution reaction (OER). Herein, we report the preparation of a cobalt-manganese oxide spinel nanowire catalyst, where the incorporation and stabilization of high-valent cation fractions are induced by electron-withdrawing anionic fluorine groups. By the XPS, the strongly electronegative F atoms improve the ratio of Co3+/Co2+ and Mn4+/Mn3+, thereby enhancing OER activity and stability. The hydrophilicity F-MCO nanowires have a large specific surface area and great conductivity, which expose more catalytically active sites and continuously promotes oxygen evolution. The proposed F-MCO catalyst requires only an overpotential of 210 mV at the current density of 10 mA cm−2 and can maintain stable operation for more than 100 h. And a photovoltaic-electrolysis device with the F-MCO electrocatalyst delivers a solar-to-hydrogen efficiency of 15.1 %.

中文翻译：

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氟掺杂诱导的高价钴锰尖晶石纳米线用于持久的酸析氧反应


高价金属阳离子比例的增加对于提高不含贵金属的催化剂在酸性析氧反应（OER）中的稳定性具有重要意义。在此，我们报道了钴锰氧化物尖晶石纳米线催化剂的制备，其中高价阳离子部分的掺入和稳定是由吸电子阴离子氟基团诱导的。通过XPS，强电负性的F原子提高了Co3+/Co2+和Mn4+/Mn3+的比率，从而增强了OER活性和稳定性。亲水性F-MCO纳米线具有较大的比表面积和良好的导电性，暴露出更多的催化活性位点并持续促进氧气析出。所提出的F-MCO催化剂在10 mA cm−2的电流密度下仅需要210 mV的过电势，并且可以保持稳定运行超过100 h。采用 F-MCO 电催化剂的光伏电解装置可实现 15.1% 的太阳能制氢效率。