Pulsed laser deposition of nanocomposite MoSex/Mo thin-film catalysts for hydrogen evolution reaction

•Pulsed laser irradiation of MoSe2 target results in Mo nanoparticle formation.•Incorporation of Mo particles modifies the nanostructure of thin MoSex films.•Vertically aligned molecular layers were formed around the nanoparticles.•Nanocomposite films are highly efficient catalysts for hydrogen evolution reaction.

Pulsed laser irradiation (wavelength 1.06 μm) of a molybdenum diselenide target in vacuum caused the formation of Mo-enriched particles on the surface of the target. Nanoparticles ~ 5–50 nm in size were torn from the target and deposited on the substrate. The use of a buffer gas (argon, pressure 5 Pa) increased the thickness of the shells formed around the nanoparticles and modified the chemical composition of the films. Heating the substrate caused the crystallization of the matrix, such that the basal planes were oriented in a direction parallel to the film surface. The orientation of the planes changed in the shells. The edge sites occurred at the film surface, exhibiting the enhanced catalytic activity in hydrogen evolution reaction. The deposition of MoSex/Mo films in a nanocrystalline state on the carbon electrode caused a decrease in the overvoltage of more than 270 mV, and the lowest Tafel slope was 86 mV/dec.