Electron Transport Chains Promote Selective Photocatalytic Conversion of CO2 to Methanol

Abstract

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.