Nanostructured MoS3/WSe2 Thin-Film Photocathode for Efficient Water Splitting Under Light Illumination

The influence of the chemical state of a WOy thin-film precursor on formation of WSe2 nanofilms under rapid selenization on a glassy carbon substrate at 900 degrees C is studied. A nanolayer of amorphous molybdenum sulfide (MoSx similar to 3), which has high catalytic activity in the electrochemical reaction of hydrogen evolution, is applied onto the surface of the obtained WSe2 films by pulsed laser deposition. It is shown that the composition of the WOy thin-film precursor has a significant effect on the morphology of the WSe2 nanolayers, and this characteristic largely determines the efficiency of hydrogen evolution by the MoS3/WSe2 heterostructure upon photoactivated water splitting. The most efficient hydrogen evolution is found for the MoS3/WSe2 photocathode heterostructure containing WSe2 in the form of crystal petals of similar to 50 nm in thickness, with these crystals oriented perpendicular to the substrate surface. A theoretical analysis of the possible effect of synergistic interaction at the MoS3/WSe2 interface on the efficiency of hydrogen evolution is carried out. Density functional theory calculations have shown that MoS3 clusters can increase the efficiency of the hydrogen evolution reaction upon contact with surface regions of WSe2 nanocrystals different in atomic packing.

Automated summary

The chemical state of a WOy thin-film precursor significantly affects the morphology of WSe2 nanofilms and the efficiency of hydrogen evolution in the MoS3/WSe2 heterostructure during photoactivated water splitting. The interaction at the MoS3/WSe2 interface can increase the hydrogen evolution efficiency by enhancing the reaction on surface regions of WSe2 nanocrystals with different atomic packing.