Pulsed Laser Deposition of Nanostructured MoS/np-Mo//WO Hybrid Catalyst for Enhanced (Photo) Electrochemical Hydrogen Evolution.

Pulsed laser ablation of MoS and WO targets at appropriate pressures of background gas (Ar, air) were used for the preparation of new hybrid nanostructured catalytic films for hydrogen production in an acid solution. The films consisted of a nanostructured WO underlayer that was covered with composite MoS/np-Mo nanocatalyst. The use of dry air with pressures of 40 and 80 Pa allowed the formation of porous WO films with cauliflower- and web-like morphology, respectively. The ablation of the MoS target in Ar gas at a pressure of 16 Pa resulted in the formation of amorphous MoS films and spherical Mo nanoparticles. The hybrid MoS/np-Mo//WO films deposited on transparent conducting substrates possessed the enhanced (photo)electrocatalytic performance in comparison with that of any pristine one (MoS/np-Mo or WO films) with the same loading. Modeling by the kinetic Monte Carlo method indicated that the change in morphology of the deposited WO films could be caused by the transition of ballistic deposition to diffusion limited aggregation of structural units (atoms/clusters) under background gas pressure growth. The factors and mechanisms contributing to the enhancement of the electrocatalytic activity of hybrid nanostructured films and facilitating the effective photo-activation of hydrogen evolution in these films are considered.