Graphene-induced growth of Co3O4 nanoplates with modulable oxygen vacancies for improved OER properties

Abstract

Transition metal oxide/hydroxide is intensively studied for the oxygen evolution reaction (OER). Herein, the graphene-induced growth of Co₃O₄ nanoplates with modulable oxygen vacancies via a hydrothermal treatment is reported. With the increase of reaction time before the formation of Co(OH)₂, the oxygen vacancies and conductivity of Co₃O₄ nanoplates continued to increase resulting in dramatically enhanced OER performances_. An ultralow overpotential of 354 mV at a current density of 100 mA cm⁻² and a Tafel slope as low as 63.24 mV dec⁻¹ in 1 M KOH solution were obtained, superior to those of most reported oxides and RuO₂.