Boosting electrocatalytic oxygen evolution activity of bimetallic CoFe selenite by exposing specific crystal facets

Abstract

It was of great significance to develop efficient and stable electrocatalysts for oxygen evolution reactions via simple and environmentally-friendly methods. Herein, by changing the reaction conditions, we prepared a unique rod-like bimetallic CoFe selenite with different exposure of crystal facets via a surfactant-free hydrothermal method. Then, via in situ calcination under N₂ atmosphere at different temperatures, the optimal calcined sample, namely NC₄FS-350, showed excellent OER performance of 235 mV@10 mA cm⁻² and Tafel slope of 56.1 mV dec⁻¹ on a glassy carbon electrode, which should be ascribed to its abundant activity sites and improved instinct activity from its improved electronic conductivity, faster mass transfer and electrolyte diffusion, derived from the unique chemical composition and amorphous mesoporous structure. This study provides an efficient strategy to design and develop earth abundant electrocatalysts in the field of energy storage and conversion.