All-organic Z-scheme photoreduction of CO2 with water as the donor of electrons and protons

Abstract Carbon nitrides and flavins are two classes of easy accessible transition metal-free, photoactive materials. Their photocatalytic efficiency to enable a variety of chemical reactions is well documented. Here, we report on their combination in one photocatalytic system by designing biomimetic non-spherical core-shell architectures comprising micro-sized crystals of flavins decorated by potassium poly(heptazine imide) nanoparticles on the surface. The designed non-spherical core-shell composites are tested in the photocatalytic CO2 reduction to CH4, MeOH, EtOH and CO using water vapor as a donor of electrons and protons at the gas-solid interface. The forged Z-scheme heterojunction between these two materials allows increasing of their photocatalytic performance. Whereby excited states lifetimes are extended by interface charge recombination and photoredox processes are boosted because of an overall wider band gap.