Oxygen vacancies enable modulating the dissolution of metal cations and surface reconstruction of transition metal oxides into metal oxyhydroxide for oxygen evolution reaction (OER), while the intrinsic reconstructing mechanism is still undiscovered. Herein, CoMoO with an optimal level of oxygen vacancy experiences controllable reconstruction into CoOOH, which holds an ultralow overpotential of 234 mV at a current density of 10 mA cm and low Tafel slope of 58 mV dec, and its intrinsic catalytic activity increases around 57%. Raman spectroscopy indicates oxygen vacancies stimulate the formation of amorphous hydrous Co(OH) as an intermediate at a lower potential, accompanied by the eruptive evolution into well-crystallized CoOOH with potential rising as small as 0.05 V. Coherent reconstructing behaviours intermediated by oxygen vacancy also validates in CoWO and CoVO, opening one brilliant and universal avenue to tune OER activity of metal oxyhydroxides precisely in controllable manners.

中文翻译：

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氧空位介导的钴基氧化物表面重构的内在机制

氧空位能够调节金属阳离子的溶解和过渡金属氧化物的表面重构为金属羟基氧化物以进行析氧反应（OER），而内在的重构机制尚未被发现。其中，具有最佳氧空位水平的CoMoO可可控重构为CoOOH，在10 mA cm的电流密度下具有234 mV的超低过电势和58 mV dec的低塔菲尔斜率，其内在催化活性提高了约57% 。拉曼光谱表明，氧空位在较低电势下刺激形成无定形水合 Co(OH)2 作为中间体，并伴随着喷发演化成结晶良好的 CoOOH，电势上升小至 0.05 V。氧空位还介导了相干重构行为在 CoWO 和 CoVO 中进行了验证，开辟了一种以可控方式精确调节金属羟基氧化物的 OER 活性的辉煌且通用的途径。