Phase-selective modulation of TiO 2 for visible light-driven C–H arylation: Tuning of absorption and adsorptivity

Abstract

© 2019 Elsevier B.V. To understand and modify TiO 2 for organic photoreaction, two points are important: improving light absorption and retaining adsorption sites for organic reagents. Herein, we tuning the absorption and adsorption of TiO 2 by introducing the defects on each phase of TiO 2 , called phase-mixed structures of ordered anatase (OA) and disordered rutile (DR) (OA/DR P25) and disordered anatase (DA) and ordered rutile (OR) (DA/OR P25). Disordered structure of TiO 2 broadened the absorption wavelength range including visible light, but changed surface structure reduced the adsorptivity of organic reactant. Additionally, anatase and rutile phase of TiO 2 has different surface properties and energy band structure, so keeping the crystalline anatase surface for adsorption was important while introducing the TiO 2 . Thus, it is assumed that the phase combination of OA and DR can be the best photocatalytic structure of TiO 2 even without any supporting materials and/or co-catalysts. In fact, the arylation yield of OA/DR P25 is the highest (63.4%), compared to those of untreated P25 (40.0%) and DA/OR (20.1%), highlighting the potential of OA/DR P25 in various visible light-driven photocatalytic organic reactions