Protecting TiS3 photoanodes for water splitting in alkaline media by TiO2 coatings

Titanium trisulfide (TiS3) nanoribbons, when coated with titanium dioxide (TiO2), can be used for water splitting in the KOH electrolyte. TiO2 shells can be prepared through thermal annealing to regulate the response of TiS3/TiO2 heterostructures by controlling the oxidation time and growth atmosphere. The thickness and structure of the TiO2 layers significantly influence the photoelectrocatalytic properties of the TiS3/TiO2 photoanodes, with amorphous layers showing better performance than crystalline ones. The oxide layers should be thin enough to transfer photogenerated charge through the electrode–electrolyte interface while protecting TiS3 from KOH corrosion. Finally, the performance of TiS3/TiO2 heterostructures has been improved by coating them with various electrocatalysts, NiSx being the most effective. This research presents new opportunities to create efficient semiconductor heterostructures to be used as photoanodes in corrosive alkaline aqueous solutions.