Photoinduced activation of CO₂ on Ti-based heterogeneous catalysts: Current state, chemical physics-based insights and outlook

This article is a review of the current knowledge of the chemical physics of carbon dioxide (CO₂) conversion to fuels using light energy and water (CO₂ photoreduction) on titania (TiO₂)-based catalysts and Ti-species in porous materials. Fairly comprehensive literature reviews of CO₂ photoreduction are available already. However, this article is focused on CO₂ photoreduction on Ti-based catalysts, and incorporates fundamental aspects of CO₂ photoreduction, knowledge from surface science studies of TiO₂ and the surface chemistry of CO₂. Firstly, the current state of development of this field is briefly reviewed, followed by a description of and insights from surface state and surface site approaches. Using examples such as metal-doping of TiO₂, dye-sensitization, oxygen vacancies in TiO₂ and isolated-Ti centers in microporous/mesoporous materials, the utility of these approaches to understand photoinduced reactions involved in CO₂ activation is examined. Finally, challenges and prospects for further development of this field are presented. Enhanced understanding of the CO₂ : TiO₂ system, with a combination of computational and experimental studies is required to develop catalysts exhibiting higher activity towards CO₂ photoreduction.