Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an l-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS₂ (SnS₂-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO₂ to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS₂ lattice, resulting in different photophysical properties as compared with undoped SnS₂. This SnS₂-C photocatalyst significantly enhances the CO₂ reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS₂-C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO₂ reduction under visible light, where the in situ carbon-doped SnS₂ nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.

Photocatalytic conversion of carbon dioxide (CO₂) to hydrocarbons such as methanol makes possible simultaneous solar energy harvesting and CO₂ reduction, two birds with one stone for the energy and environmental issues. This work describes a high photocatalytic conversion of CO₂ to methanol using graphene oxides (GOs) as a promising photocatalyst. The modified Hummer's method has been applied to synthesize the GO based photocatalyst for the enhanced catalytic activity. The photocatalytic CO₂ to methanol conversion rate on modified graphene oxide (GO-3) is 0.172 μmol g cat⁻¹ h⁻¹ under visible light, which is six-fold higher than the pure TiO₂.