TiO₂ Nanosheet Arrays with Layered SnS₂ and CoO_x Nanoparticles for Efficient Photoelectrochemical Water Splitting

Converting solar energy into sustainable hydrogen fuel by photoelectrochemical (PEC) water splitting is a promising technology to solve increasingly serious global energy supply and environmental issues. However, the PEC performance based on TiO₂ nanomaterials is hindered by the limited sunlight-harvesting ability and its high recombination rate of photogenerated charge carriers. In this work, layered SnS₂ absorbers and CoO_x nanoparticles decorated two-dimensional (2D) TiO₂ nanosheet array photoelectrode have been rationally designed and successfully synthesized, which remarkably enhanced the PEC performance for water splitting. As the result, photoconversion efficiency of TiO₂/SnS₂/CoO_x and TiO₂/SnS₂ hybrid photoanodes increases by 3.6 and 2.0 times under simulated sunlight illumination, compared with the bare TiO₂ nanosheet arrays photoanode. Furthermore, the TiO₂/SnS₂/CoO_x photoanode also presented higher PEC stability owing to CoO_x catalyst served as efficient water oxidation catalyst as well as an effective protectant for preventing absorber photocorrosion.