Oxygen vacancy improves the hydrogen evolution reaction property of WO3−x nanosheets

WO3−x nanosheets are at the first time reported on Ni foam (NF) directly without the binder. Due to low electron conductivity of WO3−x, NF as the substitute is a better choice to improve performances of WO3−x nanosheets electrodes. On the other hand, WO3−x with unsaturated valence annealed at 400 °C in Ar/H2 can increase the defect and improve the performances of hydrogen evolution reaction (HER). As catalyst for HER, WO3−x/NF exhibits better catalytic activity and stability than WO3/NF with overpotentials of 175 mV and 260 mV at the current densities of 10 mA cm−2 and 50 mA cm−2, respectively. In addition, WO3−x/NF has superior durability and stability for 105 h in the long-term electrochemical process. This study provides a new direction in the design and development of transition metal oxides (TMOs) as high activity HER catalysts for practical applications.