Application of Pulsed Laser Deposition in the Preparation of a Promising MoSx/WSe2/C(B) Photocathode for Photo-Assisted Electrochemical Hydrogen Evolution

We studied the possibility of using pulsed laser deposition (PLD) for the formation of a MoSx/WSe2 heterostructure on a dielectric substrate. The heterostructure can be employed for effective solar water splitting to produce hydrogen. The sapphire substrate with the conducting C(B) film (rear contact) helped increase the formation temperature of the WSe2 film to obtain the film consisting of 2H-WSe2 near-perfect nanocrystals. The WSe2 film was obtained by off-axis PLD in Ar gas. The laser plume from a WSe2 target was directed along the substrate surface. The preferential scattering of selenium on Ar molecules contributed to the effective saturation of the WSe2 film with chalcogen. Nano-structural WSe2 film were coated by reactive PLD with a nanofilm of catalytically active amorphous MoSx similar to 4. It was established that the mutual arrangement of energy bands in the WSe2 and MoSx similar to 4 films facilitated the separation of electrons and holes at the interface and electrons moved to the catalytically active MoSx similar to 4. The current density during light-assisted hydrogen evolution was above similar to 3 mA/cm(2) (at zero potential), whilst the onset potential reached 400 mV under irradiation with an intensity of 100 mW/cm(2) in an acidic solution. Factors that may affect the HER performance of MoSx similar to 4/WSe2/C(B) structure are discussed.

Automated summary

Research has shown that the MoSx/WSe2 heterostructure formed by pulsed laser deposition on a dielectric substrate can be used for effective solar water splitting to produce hydrogen, with the formation conditions of the WSe2 film and the separation of electrons and holes playing crucial roles in the reaction.