Advances in Noble Metals Modified g-C3N4 Heterostructures towards Enhanced Photocatalytic Redox Ability

The photocatalytic activities of catalysts depend on energy harvesting ability and the separation/transport of photogenerated carriers. The surface plasmon resonance (SPR) of noble metal nanoparticles (e.g., Cu, Au, Pd etc.) can be adjusted in the entire visible region via varying the nanocomponents of the material to attain enhanced light absorption capacity of graphitic carbon nitride (g-C3N4) based composites. With the SPR of noble metals been able to enhance the local electromagnetic field and improve the interband transition as well as the resonant energy transfer occurred from the plasmonic dipoles to electron-hole pairs via near-field electromagnetic interactions, noble metals have been quite popular nanocomponents materials in the case of g-C3N4 modification for the applications of CO2 photoreduction and water splitting. Herein, recent key advances in noble metals (either in single atom, cluster, or nanoparticle forms) and inorganic/organic nanocomponents incorporated g-C3N4 nanosheets based composite photocatalysts with improved photoinduced charge mobility are systematically discussed, particularly, the significant applications of these photocatalysts in CO2 photo-conversion and H2 production. Issues related to the different types of multi-nanocomponent heterostructures (involving Schottky junctions, Z-/S-scheme heterostructures, composed of noble metals and additional semiconductor nanocomponents) as well as the adjustment of dimensionality of the heterostructures (by incorporating noble metal nanoplates on g-C3N4 forming 2D/2D heterostructures) are also discussed. The current prospects and possible challenges of the noble metal (e.g., Au, Pt, Pd, and Cu) incorporated g-C3N4 composite photocatalysts, particularly in water splitting, CO2 reduction, pollution degradation, and chemical conversion applications are summarized.