Synthesis and Evaluation of Reduced Graphene Oxide (rGO) Supported on Ni₃O₄ as Spinel-Based Cathode Catalyst for the Effective Anion-Exchange Membrane Fuel Cell Application

Oxygen reduction reaction (ORR) stability and catalytic activity in high-durability anion exchange membrane fuel cells (AEMFCs) can be improved using graphene-supported spinel-based Ni₃O₄ cathode catalysts. Here, we describe a simple and economical hydrothermal method for synthesizing reduced graphene oxide (rGO) supported on Ni₃O₄. The atomic-level contribution of the Ni−Ni and Ni−O bonds to the chemical structure of nickel oxide was confirmed by X-ray photoelectron and absorption spectroscopy studies. Due to the force of the void for oxygen created by nickel atoms, Ni₃O₄@rGO for the ORR exhibited enhanced stability and catalytic activity (E_1/2=0.761 V and over 30,000 CV cycles). A single AEMFC cell achieved the greatest power density and long-term durability using a Ni₃O₄@rGO cathode, suggesting improved endurance despite the minimal voltage decrease (power density 29.6 mW cm⁻², endurance for 25 h). These findings offer insights and point to opportunities for developing metal oxide–based AEMFCs.