Structural and electrochemical properties of W-Se-O layers prepared by pulsed laser pre-deposition and thermal posttreatment

Abstract

Novel nanostructured thin-film coatings containing WSe2 and WO3 nanosheets were prepared through a simple and highly reproducible method. Pulsed laser pre-deposition of W- Se-O films on a microcrystalline graphite substrate by ablation of WSe2 target in a mixture of Ar and O2 gases was followed by thermal post-treatment. The influence of pre-deposition and post-treatment conditions on the structure, morphology and chemical composition of the W-Se- O films was studied. Thermal annealing at appropriate conditions of pre-deposited amorphous W-Se-O films resulted in the formation of crystalline structure consisted of nanocrystals of WSe2 and WO3 phases. Such structural modification significantly altered the electrochemical properties of the thin-film coatings with consequences, in particular, on their catalytic activity toward hydrogen evolution reaction in an acid solution.