Heterostructures in carbon-doped tungsten nitride and its effect on electrocatalytic properties for methanol oxidation

Abstract

The hexagonal carbon-doped tungsten nitride nanoparticles (WC|N) have been derived from the cubic WN by inducing carbon atoms to WN lattices via a controlled carbonization method. The heterostructures discrepancy in WC|N catalysts involving constitutions of crystal phases and concentration of carbon and nitrogen could be effectively adjusted by simply changing carbonization time, and then had a great impact on the electrocatalytic behaviors of WC|N. Porous morphology of WC|N catalysts was also inherited from tungsten nitrides to provide the large surface area. The ternary Pt/WC|N catalysts were fabricated by an ethylene glycol reduction method with microwave-assisted heating. The intimate contact and intensive interaction between Pt and WC|N catalyst were verified. Impressively, the Pt/WC|N hybrid exhibited superior electrocatalytic activity for methanol oxidation and improved CO anti-poisoning capacity which higher than that of commercial Pt/C catalyst. The catalytic activity was enhanced due to the large amount of distortion which was induced during the diffusion of C into WN lattice and resultant phase transformation. Samples which were carbonized for 120min displayed the outstanding catalytic activity among all the materials even from the different tungsten sources suggest that the extent of distortion in catalyst is the crucial factor for the catalyst activity in electrochemistry reaction.