Reduced Graphene Oxide-Coated Iridium Oxide as a Catalyst for the Oxygen Evolution Reaction in Alkaline Water Electrolysis.

Producing hydrogen by water electrolysis has attracted significant attention as a potential renewable energy solution. In this work, a catalyst with reduced graphene oxide (rGO) loaded on IrO/TiO (called rGO/IrO/TiO) was designed for the catalytic oxygen evolution reaction (OER). The catalyst was synthesized by coating graphene oxide onto a pretreated IrO/TiO precursor, followed by thermal treatment at 450 °C to achieve reduction and the adhesion of graphene to the substrate. The graphene support retained its intact sp carbon framework with minor oxygen-containing functional groups, which enhanced electrical conductivity and hydrophilicity. Benefiting from the synergistic effect of an rGO, IrO, and TiO matrix, the rGO/IrO/TiO catalyst only needed overpotentials of 240 mV and 320 mV to reach 10 mA cm and 100 mA cm in the OER, along with excellent stability over 50 h. Its morphology and crystalline structure were characterized by SEM and XRD spectroscopy, and its electrochemical performance was tested by LSV analysis, EIS impedance spectrum, and double-layer capacitance (C) measurements. This work introduces an innovative and eco-friendly strategy for constructing a high-performance, functionalized Ir-based catalyst.