Electron Transport Chains Promote Selective Photocatalytic Conversion of CO₂ to Methanol

The photocatalytic conversion of carbon dioxide (CO2) into “liquid sunshine” methanol (CH3OH) using semiconductor catalysts has garnered significant attention. Increasing the number of effective electrons and regulating reaction pathways is the key to improving the activity and selectivity of CH3OH. Due to the electron transport properties of semiconductor heterojunctions and reduced graphene oxide (rGO), a CoS/CoS2-rGO nanocomposite was constructed and applied to the photocatalytic reduction of CO2 to CH3OH. The optimized CoS/CoS2-rGO-5 photocatalyst achieved a CH3OH production rate of 15.26 μmol·g–1 and a selectivity of 42%, which were higher than those of CoS and CoS/CoS2. This is mainly attributed to the fact that CoS/CoS2 and rGO jointly constructed efficient electron transport chains, which not only ensure that photogenerated electrons can achieve orderly and directional migration but also innovatively establish a dual reaction site mechanism, providing strong support for improving photocatalytic activity and selectivity of CH3OH. The design of composite catalysts by coupling of semiconductor heterojunctions with carbon material affords new territory for efficient photogenerated electron transport and provides alternative pathways for photocatalytic CO2 conversion.