Construction of CuO/Cu/WO3−x/WO3/W self-supported electrodes by a dry chemical route for hydrogen evolution reaction

[Display omitted] •A dry chemical route was designed to prepare CuO/Cu/WO3−x/WO3/W heterostructure.•The structure distribution of the tungsten oxide was measured by Raman technique.•The H+ induced oxygen vacancies in the WO3−x layer largely narrow the bandgap.•The oxygen vacancies and the Cu species are both beneficial for the charge transfer. Heterostructrural electrocatalysts are promising for enhancing reaction performance by increasing the carriers mobility and lowering the activation energy. Herein, an environmentally friendly dry chemical route based on ion beam technology is designed to construct the heterostructural CuO/Cu/WO3−x/WO3/W electrocatalysts. Through H+ beam bombardment, the oxygen vacancies in the tungsten oxide are created, and the Cu species are deposited simultaneously on the surface oxidized W mesh. This fabrication leads to a significant elevation of HER performance for WO3 based electrocatalysts. The self-supported CuO/Cu/WO3−x/WO3/W electrode exhibits an overpotential of 127 mV at −10 mA cm−2 in 0.5 M H2SO4 aqueous solution, which is much better than those of the other samples without the WO3−x layer or the deposited Cu species. The H+ bombardment induced oxygen vacancies enhance the conductivity of the tungsten oxide via narrowing its bandgap, as well as provide large amounts of unsaturated W atoms that could serve as active sites. The Cu species play a role of electron mobility promoter for further enhancing the HER activity. This strategy offers a facile route for the construction of transition metal based heterostructural electrocatalysts.