Nanostructured WCx/CNTs as highly efficient support of electrocatalysts with low Pt loading for oxygenreduction reaction

Abstract

Highly active Pt–WC_x/carbon nanotube (CNT) electrocatalysts for the oxygen reduction reaction (ORR) have been developed by the combination of tungsten carbide with CNTs as electrocatalyst supports. The obtained WC_x/CNT and Pt–WC_x/CNT samples were characterized by XRD, TEM, XPS and electrochemical measurements. The results showed that nanostructured tungsten carbide particles on carbon nanotubes could be prepared by microwave-assisted thermolytic molecular precursor method, and the particle size of tungsten carbide increased with the increase of tungsten loading. The nanostructured WC_x/CNTs showed electrocatalytic activity for oxygen reduction reaction. The deposition of Pt nanoparticles on the WC_x/CNTs resulted in higher electrocatalytic activity for the oxygen reduction reaction and better immunity to methanol than Pt/CNT catalysts. The unique electrocatalytic properties of the novel Pt–WC_x/CNT electrocatalyst were attributed to a synergistic effect between Pt, WC_x and the CNTs. The findings also indicated that WC_x/CNTs were efficient electrocatalyst supports that could reduce Pt usage while the same electrocatalytic properties were kept for the ORR in direct methanol fuel cells.