FeO-Co3O4 Hybrid Composite on Oxidized Graphite: Single-Stage Hydrothermal Synthesis and Application as an Electrocatalyst for Oxygen Evolution Reaction

Abstract

The sluggish oxygen evolution reaction (OER) is one of the major factors limiting the application of water splitting for hydrogen production. This study used a single-stage hydrothermal method to synthesize highly porous FeO-Co3O4 nanoparticles on oxidized graphite (GOX) sheets. The fabrication of FeO-Co3O4@GOX nanoparticles depends on the oxidation time. The optimal catalyst (FeO-Co3O4@GOX-10) showed higher activity toward the OER than Co3O4, FeO-Co3O4, FeO-Co3O4@GOX-5, and FeO-Co3O4@GOX-24. The FeO-Co3O4@GOX-10 catalyst exhibited a low overpotential and small Tafel slope of 0.23 V and 64 mV dec−1, respectively, at a current density of 10 mA cm−2, demonstrating enhanced specific activity and turnover frequency. The optimal catalyst played a synergistic role in accelerating the electron transfer process and accelerating the OER with faradaic efficiency of 95.3%. Moreover, the improved activity of the FeO-Co3O4@GOX-10 catalyst was attributed to enhanced active site exposure, fast charge transfer, and synergistic effect of FeO-Co3O4 and GOX. This study provides a new approach for the development of efficient, stable, and environmentally friendly hybrid catalysts for energy conversion applications.