Photocatalytic water splitting performance of TiO2 sensitized by metal chalcogenides: A review

Titanium dioxide (TiO2) has been extensively studied for photocatalytic water splitting applications for more than 50 years because of its advantages, such as its low cost, abundance, good chemical stability, nontoxicity, and sufficient energy potential to oxidize and reduce water molecules. On the other hand, TiO2 has its own set of limitations, namely its wide bandgap (Eg = similar to 3.2 eV), which makes it less effective in sunlight. A few methods have been reported to overcome these problems, one of which is to make a heterojunction composite with other materials. The added material can inject electrons directly into the conduction band of TiO2 and provide a tiered band structure, which can reduce the occurrence of photogenerated electron and hole recombination. Currently, the research and development of heterojunctions consisting of TiO2 with chalcogenide materials has attracted the attention of many researchers. Metal chalcogenides offer a number of advantages, including absorption onset tuning, a size-dependent bandgap that can lead to high theoretical quantum efficiencies, effective charge transfer to the conduction band when TiO2 is exposed to visible light, and high photochemical stability. In this review, the performance of various TiO2/metal chalcogenide heterojunctions for photoelectrochemical water splitting is presented. The role of most common metal chalcogenides in TiO2 will be exposed. Finally, the review concludes with a summary and recommendations for further research on this hot issue.

Automated summary

This review presents the performance of TiO2/metal chalcogenide heterojunctions for photoelectrochemical water splitting, highlighting the role of metal chalcogenides in TiO2. It also provides recommendations for further research on this topic.