Synergistic Tricomponent Pt–Co3O4–WO3 on a Carbon Electrocatalyst for Efficient Bifunctional Oxygen Electrocatalysis for Sustainable Regenerative PEM Fuel Cells

Abstract

The efficiency of bifunctional electrocatalysts capable of promoting both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) efficiently is a key factor that strongly influences the performance of regenerative proton exchange membrane fuel cells (RPEMFCs). Nevertheless, achieving high catalytic activity, stability, and effective charge transfer with traditional catalysts remains a significant challenge. In this work, a tricomposite platinum (Pt)/cobalt oxide (Co3O4)/tungsten oxide (WO3) catalyst on carbon (C–Pt/Co3O4/WO3) is synthesized through a hydrothermal process followed by a sequential chemical reduction method. The synergistic metal–mixed metal oxide–carbon interface produced by the addition of Co3O4 and WO3 to Pt is formed as a homogeneous porous nanoparticle with rich active sites for the OER and ORR and a high specific surface area as evidenced by BET (Brunauer–Emmett–Teller) results. The electrochemical results show that the as-proposed catalyst has superior bifunctional activity, with an OER overpotential of about 280 mV at a current density of 10 mA cm–2 and an ORR onset potential of 0.90 V versus the RHE. This leads to a bifunctional potential difference of 0.63 V. Tafel slope analysis suggests good charge transfer kinetics (68 mV dec–1 for the OER, 72 mV dec–1 for the ORR) and a low charge transfer resistance of 3.69 Ω. It maintained most of the electrocatalytic activity even after 5000 potential cycles, showing great stability. In addition, cyclic voltammetry demonstrates an ECSA (electrochemical surface area) of 65–67 m2 g–1, which is even better than that of a commercial Pt/C catalyst; this result indicates that the synthesized material C–Pt/Co3O4/WO3 catalyst is suitable for efficient RPEMFCs.