Effect of Vanadium Doping on the Catalytic Activity of MoO₂ Thin Films in Hydrogen Evolution Reaction

Recently, Mo-based materials have emerged as promising candidates to replace Pt catalysts for hydrogen evolution reaction. Among these, MoO₂ holds a great promise due to its metallic conductivity. Here, we investigate the effect of V doping on the hydrogen evolution reaction activity of MoO₂ thin films. V doped MoO₂ thin films with different dopant concentrations were prepared on conductive Si substrates by co-sputtering followed by thermal sulfurization. The electrochemical measurements revealed that V doping has an adverse effect on the hydrogen evolution reaction performance of MoO₂ films, attributed to the p-type doping nature of V. This study gives insight into the effect of dopant type on the catalytic activity of hydrogen evolution reaction catalysts and provides a hint for the correct selection of dopant elements to enhance the activity of the existing catalyst materials.