Modulating g-C3N4-based van der Waals heterostructures with spatially separated reductive centers for tandem photocatalytic CO2 methanation

Selective conversion CO2 to hydrocarbons over g-C3N4 photocatalyst remains a great challenge. Herein, efficient photocatalytic CO2 conversion to CH4 via a unique tandem pathway is achieved over strongly coupled van der Waals (vdW) heterostructure, composed of K+-intercalated crystalline g-C3N4 nanorods (CCNR) and N-doped porous carbon (NPC). A superior CH4 selectivity of 90.2% with an outstanding evolution rate of 11.79 mu mol g-1 h-1 is demonstrated over optimized CCNR-NPC vdW heterostructure decorated with Pt species, without any sacrificial agents. The radial (intralayer) photoelectrons and axial (interlayer) photoelectrons transfer towards the exposed terminal NHx-sites at CCNR edge and the NPC-immobilized Pt-sites, respectively, giving rise to two separated spatially but cooperative reductive centers. At terminal NHx-sites, CO2 is activated to *CO intermediates, which are hydrogenated into CH4 at NPC-immobilized Pt-sites. This work will offer a new perspective for selective tandem photocatalytic CO2 conversion by designing hybrid photocatalysts with spatially separated but cooperative active centers.

Automated summary

Researchers achieved efficient photocatalytic conversion of CO2 to CH4 through a strongly coupled van der Waals heterostructure. The optimized structure, decorated with precious metal Pt, demonstrated a CH4 selectivity of 90.2% and an evolution rate of 11.79 mu mol g-1 h-1 without the need for sacrificial agents. By enabling photoelectron transfer and the presence of separate but cooperative reduction centers, CO2 was converted to CH4. This study offers a new perspective for selective tandem photocatalytic CO2 conversion by designing hybrid photocatalysts with spatially separated but cooperative active centers.