Due to the slow kinetic nature of the oxygen evolution reaction (OER), the development of electrocatalysts with high efficiency, stability, and economy for oxygen production using metal–organic framework (MOF) materials is still a challenging research topic. In this work, we chose the different concentrations of FeS adsorption to encapsulate metal cobalt-based ZIF-67 MOF for preparing a series of electrocatalysts (ZIF₁FeS_x, x = 0.2, 0.5, 0.75, and 1), which were mainly explored for the electrocatalytic OER. Among them, ZIF₁FeS_0.5 has excellent electrocatalytic activity for OER, which can be driven by low overpotentials of 276 and 349 mV at 10 and 50 mA cm^–2 current densities, and more than 92% of the initial overpotential can be maintained after 100 h of continuous OER at 10 mA cm^–2 current density. This is mainly due to the electronic interactions between the cobalt-based MOF and the FeS, which shift the electronic state of the active metal center to a higher valence state for increasing the number of active sites and enhancing the efficiency of electron transfer to facilitate the OER course. This work may contribute to the design of effective catalysts for the OER during the electrolysis of alkaline solutions.

中文翻译：

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不同 FeS 浓度的 ZIF-67 纳米材料封装用于增强氧化析出反应


由于析氧反应 （OER） 的动力学速度缓慢，使用金属有机框架 （MOF） 材料开发高效、稳定和经济的电催化剂用于制氧仍然是一个具有挑战性的研究课题。在这项工作中，我们选择了不同浓度的 FeS 吸附来封装金属钴基 ZIF-67 MOF，用于制备一系列电催化剂 （ZIF₁FeS_x， x = 0.2， 0.5， 0.75， 和 1），主要探索用于电催化 OER。其中，ZIF₁FeS_0.5 对 OER 具有优异的电催化活性，可在 10 和 50 mA cm^–2 电流密度下由 276 和 349 mV 的低过电位驱动，并且在 10 mA cm^–2 电流密度下连续 OER 100 小时后，可以维持超过 92% 的初始过电位。这主要是由于钴基 MOF 和 FeS 之间的电子相互作用，它们将活性金属中心的电子状态转变为更高的价态，从而增加活性位点的数量并提高电子转移的效率，以促进 OER 过程。这项工作可能有助于设计碱性溶液电解过程中 OER 的有效催化剂。