Protecting TiS 3 Photoanodes for Water Splitting in Alkaline Media by TiO 2 Coatings.

Titanium trisulfide (TiS 3 ) nanoribbons, when coated with titanium dioxide (TiO 2 ), can be used for water splitting in the KOH electrolyte. TiO 2 shells can be prepared through thermal annealing to regulate the response of TiS 3 /TiO 2 heterostructures by controlling the oxidation time and growth atmosphere. The thickness and structure of the TiO 2 layers significantly influence the photoelectrocatalytic properties of the TiS 3 /TiO 2 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 TiS 3 from KOH corrosion. Finally, the performance of TiS 3 /TiO 2 heterostructures has been improved by coating them with various electrocatalysts, NiS x being the most effective. This research presents new opportunities to create efficient semiconductor heterostructures to be used as photoanodes in corrosive alkaline aqueous solutions.