Plasma Treatment: a Novel Approach to Improve the Photoelectroactivity of Sb₂S₃ Thin Films to Water Splitting

Graphical Abstract

Works a treat: The non-plasma Sb₂S₃ film presents poor wettability and reduced photoelectroactivity for H₂ evolution. Once treated under nitrogen plasma, the film's surface becomes hydrophilic and the photoelectrochemical response is greatly improved. Chemical analysis shows the formation of S−N polar groups on the surface of the treated Sb₂S₃ film. The S−N group probably plays the major role in the enhancement of the wettability and photoelectroactivity.

Abstract

The present study reports a novel and fast nitrogen plasma treatment approach to boost hydrogen evolution on antimony(III) sulphide (Sb₂S₃) thin films via light-driven water splitting. The Sb₂S₃ films were synthesised by electrodepositing antimony followed by sulphurisation, and then using different treatment times under nitrogen plasma. The plasma treatment time did not result in significant changes in the microstructural and optical properties, compared to the non-plasma films. However, the wettability drastically changed from superhydrophobic for the non-plasma film to hydrophilic once treated. Photoelectrochemical analysis showed a substantial photocurrent density increase (24-fold) for the film treated for 10 s in comparison with the non-plasma film. Further characterisation by X-ray photoelectron spectroscopy and scanning electron microscopy revealed chemical and morphological modifications for the films treated, which explain the enhancement of photoelectroactivity and wettability.