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

Abstract

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 mAmgPt-1, a substantial improvement compared to the commercial Pt-based benchmark catalyst, which achieved only 212 mAmgPt-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.