Ruthenium and ruthenium oxide nanofiber supports for enhanced activity of platinum electrocatalysts in the methanol oxidation reaction

Abstract

Novel supports for the dispersion of Pt electrocatalysts in fuel cells are constantly being developed in order to improve the electrochemical performance and reduce the cost. The electrocatalytic activity and stability in fuel cells largely depend on the surface morphology and structure of the support. In this study, Ru and RuO₂ nanofibers prepared by electrospinning and post-calcination have been considered as Pt-catalyst supports. The composite material loaded with 20 wt% Pt catalyst exhibited a high anodic current density of 641.7 mA mg_Pt⁻¹, a high I_F/I_B ratio of 1.9, and excellent electrocatalytic stability compared to commercial Pt/C. The improved anodic current density of the composite is attributed to the high dispersion of the Pt catalyst over the large surface area of the nanosized support grains, while its low onset potential, high I_F/I_B ratio, and excellent electrocatalytic stability are ascribed to a bifunctional effect resulting from the existence of Ru atoms on the support surface. Finally, the efficient electron transfer and a rapid diffusion rate of the electrolyte are due to the unique network structure of the supports. Thus, the Ru and RuO₂ nanofiber composites act as promising Pt-catalyst supports for the methanol oxidation reaction.