论文题目：Self-Optimized Metal-Organic Framework Electrocatalysts with Structural Stability and High Current Tolerance for Water Oxidation

论文作者：Chaopeng Wang, Yang Feng, Hao Sun, Yurou Wang, Jun Yin, Zhenpeng Yao, Xianhe Bu*, Jian Zhu

发表期刊：ACS Catalysis, 11(12), 7132-7143, 2021   

Abstract： 

Metal-organic frameworks (MOFs) as electrocatalysts for oxygen evolution  reaction (OER) typically suffer from fast degradation under harsh  electrolyte conditions, impeding their practical use in industrial  electrolyzers. Besides, the evolution of catalytic centers in MOFs and  the related influence on their performance along the progress of  reaction have rarely been studied. Here, we report a type of  structurally stable bimetallic FeNi-MOF nanoarrays with self-optimized  electrocatalytic activities in the oxygen production. Such a unique  dynamic phenomenon is related with the gradual valence increments of Fe  ions in MOFs, which trigger the continuous performance improvement  before reaching an optimal steady state. Apart from the intact  crystalline structures upon cycling, these FeNi-MOFs achieve low  overpotentials of 239 and 308 mV at the current densities of 50 and 200  mA cm(-2), respectively, and show durable operation for over 1033 h  (>43 days) at 100 mA cm(-2) and for another 200 h at 500 mA cm(-2). A  direct comparison of isostructural and single crystalline Fe-MOFs and  Ni-MOFs resolves higher activities of Fe sites in the bimetallic MOFs,  which are corroborated by theoretical calculations. The Fe-O bond  covalency increment during Fe oxidation enhances the proton-electron  transfers with the oxygen 2p-band closer to the Fermi level, thereby  expediting the OER process. This work provides deep insights into the  understanding of catalytic processes in heterometallic MOFs.