Metal–organic frameworks (MOFs) as promising electrocatalysts have been widely studied, but their performance is limited by conductivity and coordinating saturation. This study proposes a cationic (V) modification strategy and evaluates its effect on the electrocatalytic performance of CoFe–MOF nanosheet arrays. The optimal V–CoFe–MOF/NF electrocatalyst exhibits excellent oxygen-evolution reaction (OER)/hydrogen-evolution reaction (HER) performance (231 mV at 100 mA cm^–2/86 mV at 10 mA cm^–2) in alkaline conditions, with its OER durability exceeding 400 h without evident degradation. Furthermore, as a bifunctional electrocatalyst for water splitting, a small cell voltage is achieved (1.60 V at 10 mA cm^–2). The practicability of the catalyst is further evaluated by membrane electrode assembly (MEA), showing outstanding activity (1.53 V at 10 mA cm^–2) and long-term stability (at 300 mA cm^–2). Moreover, our results reveal the apparent reconstruction properties of V–CoFe–MOF/NF in alkaline electrolytes, where the partially dissolved V promotes the formation of more active β-MOOH. The mechanism study shows the OER mechanism shifts to a lattice oxygen oxidation mechanism (LOM) after V doping, which directly avoids complex multistep adsorption mechanism and reduces reaction energy. This study provides a cation mediated strategy for designing efficient electrocatalysts.

中文翻译：

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通过阳离子工程改变析氧反应途径以激活金属有机框架中的晶格氧


金属有机框架（MOF）作为有前途的电催化剂已被广泛研究，但其性能受到电导率和配位饱和度的限制。本研究提出了一种阳离子（V）修饰策略，并评估了其对 CoFe-MOF 纳米片阵列电催化性能的影响。最佳的V-CoFe-MOF/NF电催化剂表现出优异的析氧反应（OER）/析氢反应（HER）性能（100 mA cm时为231 mV ^–2 /10 mA cm时为86 mV < b1>）在碱性条件下，OER耐久性超过400小时，无明显降解。此外，作为水分解的双功能电催化剂，实现了小电池电压（10 mA cm ^–2 时为1.60 V）。通过膜电极组件（MEA）进一步评估了催化剂的实用性，显示出优异的活性（10 mA cm ^–2 时为1.53 V）和长期稳定性（300 mA cm ^–2