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

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 (1640.58 ppm g⁻¹ h⁻¹, 1.13 μmol g⁻¹ h⁻¹) as compared to anatase TiO₂ nanoparticles (546.98 ppm g⁻¹ h⁻¹, 0.38 μmol g⁻¹ h⁻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.