Efficient solar light photoreduction of CO2 to hydrocarbon fuels via magnesiothermally reduced TiO2 photocatalyst

Abstract

Elevated atmospheric CO2 levels are recognized as a key driver of global warming. Making use of sunlight to photoreduce CO2, in turn fabricating hydrocarbon fuels compatible with the current energy infrastructure, is a compelling strategy to minimize atmospheric CO2 concentrations. However, practical application of such a photocatalytic system requires significant efforts for improved photoreduction performance and product selectivity. Herein, we investigate the performance of our newly developed reduced TiO2, prepared by a reduction process using Mg in 5% H2/Ar, for photoconversion of CO2 and water vapor to hydrocarbons, primarily CH4. Using Pt nanoparticles as a co-catalyst, under simulated solar light irradiation the reduced anatase TiO2 exhibits a relatively stable performance with a threefold increase in the rate of CH4 production (1640.58ppmg−1h−1, 1.13μmolg−1h−1) as compared to anatase TiO2 nanoparticles (546.98ppmg−1h−1, 0.38μmolg−1h−1). The improved photocatalytic performance is attributed to enhanced light absorption, suitable band edge alignment with respect to the CO2/CH4 redox potential, and efficient separation of photogenerated charges. Our results suggest that the Pt-sensitized reduced TiO2 can serve as an efficient photocatalyst for solar light CO2 photoreduction. © 2017 Elsevier B.V.