Incorporation of tantalum ions enhances the electrocatalytic activity of hexagonal WO3 nanowires for hydrogen evolution reaction

WO3 has been identified as a promising candidate electrocatalyst for hydrogen evolution reaction (HER), because it can form a tungsten bronze (HxWO3) which is highly electron and proton conducting. In this paper, we report that the electrocatalytic activity of WO3 for HER can be enhanced by incorporation of tantalum ions (Ta5+) into the lattice of WO3. The most active performance is achieved with the molar ratio of Ta/W being 0.01, which is two times more active than that of undoped WO3 at an overpotential of -0.52 V. It is shown that incorporation of proper Ta5+ into WO3 can induce moderate defects and oxygen vacancies, as well as intercalate a higher amount of protons, which enhance the electron transfer and short the protons diffusion paths. These changes correlated positively with the enhanced catalytic HER activity. This study demonstrates, for the first time, that metal ions-doped WO3 nanowires are promising electrocatalysts for HER.