Rational construction of a CdS/reduced graphene oxide/TiO₂ core-shell nanostructure as an all-solid-state Z-scheme system for CO₂ photoreduction into solar fuels

Mimicking natural photosynthesis in green plants, an all-solid-state Z-scheme was constructed for photocatalytic reduction of CO₂ in the presence of water vapor, consisting of CdS nanospheres (CdS NSs) and TiO₂ nanoparticles as photocatalysts, and reduced graphene oxide (rGO) as a solid electron mediator. In this Z-scheme system, the photogenerated electrons from the conduction band of TiO₂ transfer to rGO, and then recombine with the existing holes of CdS NSs, allowing the photo-generated electrons to enrich on the CdS semiconductor and holes on the TiO₂. The photocatalytic efficiency of the Z-scheme system exhibits remarkable enhancement relative to pure CdS, CdS/TiO₂, and CdS/rGO.