Multi-dimensional PtRu/Co₃O₄-Activated carbon Nano-Electrocatalyst: Metal–Support Interaction, and electronic contributions towards methanol electrooxidation in alkaline fuel cells

In this work, we report PtRu alloy system supported on Co₃O₄-activated carbon (Co₃O₄-C) prepared by direct reduction of H₂PtCl₆ and RuCl₃ solutions as a highly active and durable electrocatalyst for methanol oxidation reaction. The electrochemical activity of the electrocatalysts was evaluated using electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), cyclic voltammetry (CV), and chronoamperometry (CA). The formation of PtRu alloy on the Co₃O₄-C matrix, as well as their electronic interactions, is confirmed by employing X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The electrocatalysts showed distinct electrocatalytic activity in alkaline medium, depending on whether the catalysts contained PtRu alloy and whether they were supported on the hybrid Co₃O₄-C, proving their unique contributions to the electrocatalytic reaction. Benefiting from the strong metal-support interaction (SMSI) and electronic interaction between Pt and Ru, the PtRu/Co₃O₄-C displayed a highly efficient electrocatalytic performance with a mass activity of 6709 mAmg_Pt^-1, a substantial improvement compared to the commercial Pt-based benchmark catalyst, which achieved only 212 mAmg_Pt^-1. Furthermore, the PtRu/Co₃O₄-C showed excellent stability after 10 000 s, high durability after 500 cycles retaining 94 % of current density, and higher tolerance for CO. This enhanced catalytic performance can be attributed to the small nanoparticle sizes, high dispersion, large ECSA of 102.1 m²/g, and the synergy resulting from electronic coupling interactions.