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, NiS being the most effective. This research presents new opportunities to create efficient semiconductor heterostructures to be used as photoanodes in corrosive alkaline aqueous solutions.