Improving the photocatalytic reduction of CO2 to CO for TiO2 hollow spheres through hybridization with a cobalt complex

Abstract

A chemical system with enhanced efficiency for electron generation and transfer was constructed by the integration of TiO₂ hollow spheres with [Co(bipy)₃]²⁺. The introduction of [Co(bipy)₃]²⁺ remarkably enhances the photocatalytic activity of pristine semiconductor photocatalysts for heterogeneous CO₂ conversion, which is attributable to the acceleration of charge separation. Of particular interest is that the excellent photocatalytic activity of the heterogeneous catalysts can be utilised for a universal photocatalytic CO₂ reduction system. Yields of 16.8 μmol CO and 6.6 μmol H₂ can be obtained after 2 h of the photoredox reaction, and the apparent overall quantum yield was estimated to be 0.66% under irradiation at λ = 365 nm. The present findings clearly demonstrate that the integration of electron mediators with semiconductors is a feasible process for the design and development of efficient photochemical systems for CO₂ conversion.