Bifunctional noble metal-based electrocatalysts to enhance the oxygen reduction process in flexible Zn-air batteries and proton exchange membrane fuel cells

The development and optimization of electrocatalysts are focused on the oxygen reduction reaction (ORR), which is a crucial electrochemical process that directly influences the durability, power density, and efficiency of flexible zinc-air batteries (ZABs) and proton exchange membrane fuel cells (PEMFCs). In this study, we developed a noble ternary-metal catalyst containing Pt-incorporated Au-Ag nanocubes deposited on reduced graphene oxide (Pt@Au-Ag/rGO) through the hydrothermal method and investigated its performance in both PEMFCs and ZABs. The incorporation of Pt into the Au–Ag catalyst significantly enhances ORR performance compared to the Au–Ag alloy, as supported by experimental results and multiple characterization techniques. The optimized Pt@Au-Ag/rGO demonstrated excellent electrocatalytic activity toward the ORR (E_onset = 0.90 V and 0.75 V in alkaline and acid media, respectively) and the oxygen evolution reaction (OER) (E_onset = 1.57 V), with lower overpotential and outstanding durability in half-cell reactions. Finally, we constructed flexible ZABs and single-cells assemblies using Pt@Au-Ag/rGO composite as the cathode. The system demonstrated enhanced power densities, achieving 92.7 mW cm⁻² at 150 mA cm⁻² and 133.9 mW cm⁻² at 334.3 mA cm⁻².