Enhanced Oxygen Evolution by Activating Vacancy Defects on Metal–Organic Framework-Derived Co3O4/NC

Abstract

Engineering vacancy defects is a critical approach to modulating the properties of catalytic materials. However, the development of highly efficient vacancy defect catalysts and the investigation of their roles and effects remain challenging. In this study, nitrogen-doped carbon-coated Co₃O₄ porous nanomaterials were synthesized using ZIF-67 as a sacrificial template. Subsequently, through vacuum heat treatment, nitrogen-doped carbon-coated Co₃O₄ porous nanomaterials with an appropriate amount of oxygen vacancies were finally obtained. This material exhibits excellent oxygen evolution reaction (OER) catalytic activity. At a current density of 10 mA cm⁻², the overpotential is only 293 mV, and it has good cyclic stability. The existence of oxygen vacancies has been confirmed by various characterization methods. Moreover, density functional theory (DFT) calculations show that oxygen vacancies can enhance the electrical conductivity of the material, optimize the binding energy of the intermediates in the OER, and significantly improve the catalytic activity. In this study, a method of designing high-performance OER electrocatalytic materials by regulating the oxygen vacancies in the nitrogen-doped carbon-coated Co₃O₄ system is proposed, which opens up a new way for the development of efficient transition-metal-based electrocatalysts for water splitting.