Porous hypercrosslinked polymer-TiO₂-graphene composite photocatalysts for visible-light-driven CO₂ conversion

Significant efforts have been devoted to develop efficient visible-light-driven photocatalysts for the conversion of CO₂ to chemical fuels. The photocatalytic efficiency for this transformation largely depends on CO₂ adsorption and diffusion. However, the CO₂ adsorption on the surface of photocatalysts is generally low due to their low specific surface area and the lack of matched pores. Here we report a well-defined porous hypercrosslinked polymer-TiO₂-graphene composite structure with relatively high surface area i.e., 988 m² g^-1 and CO₂ uptake capacity i.e., 12.87 wt%. This composite shows high photocatalytic performance especially for CH₄ production, i.e., 27.62 μmol g^-1 h^-1, under mild reaction conditions without the use of sacrificial reagents or precious metal co-catalysts. The enhanced CO₂ reactivity can be ascribed to their improved CO₂ adsorption and diffusion, visible-light absorption, and photo-generated charge separation efficiency. This strategy provides new insights into the combination of microporous organic polymers with photocatalysts for solar-to-fuel conversion.