An ion exchange route to produce WO3 nanobars as Pt electrocatalyst promoter for oxygen reduction reaction

Abstract

WO3 nanobars with the length of 10–50nm and the width of 3–6nm on carbon (C-WO3) are synthesized through an ionic exchange route to locally anchor the metatungstate ions (W7O246−). The structures, morphologies and catalytic performance of the as-synthesized nanomaterials are characterized by various physical and electrochemical methods. The results indicate that Pt nanoparticles supporting on C-WO3 (Pt/C-WO3) are highly active and stable as cathode electrocatalyst for fuel cells. On one hand, a mass activity of 174.6mAmg−1Pt at 0.9V is obtained for oxygen reduction reaction (ORR), which is much higher than that on commercial Pt/C electrocatalyst (98.6mAmg−1Pt). On the other hand, Pt/C-WO3 electrocatalyst shows excellent electrochemical stability than Pt/C. The origin of these improvements in the catalytic activity can be attributed to the synergistic or promotion effect of WO3 on Pt. The improvement in the electrochemical stability is due to and also explains the stronger interaction force between Pt and WO3 than that between Pt and C. The present method is simple and effective, which can be readily scale up for the production of other nanomaterials as well as WO3.