An ion exchange route to produce carbon supported nanoscale vanadium carbide for electrocatalysis

Abstract

We demonstrate that vanadium carbide nanocrystals down to 2 nm on carbon (C-VC_x) can be synthesized through a novel route based on an ionic exchange process to locally anchor the species of interest by design. The structures, morphologies and catalytic performance of the as-synthesized nanomaterials were characterized by various physical and electrochemical methods. The results indicate that electrocatalysts made with Pt nanoparticles on C-VC_x (Pt/C-VC_x) are highly active and stable for both the oxygen reduction reaction (ORR) and methanol oxidation. A mass activity of 267.1 mA mg⁻¹_Pt at 0.9 V was obtained for the oxygen reduction reaction, which is much higher than that of a commercial Pt/C electrocatalyst (112.5 mA mg⁻¹_Pt). It was also demonstrated that the onset potential for methanol oxidation on Pt/C-VC_x is negatively shifted by more than 100 mV compared with that on Pt/C. The origin of these improvements in the catalytic activity can be attributed to the synergistic effect between Pt and VC_x. The novelty of the present method is its simplicity and effectiveness, and it can be readily scaled up for mass production of other nanomaterials.