Construction of a novel metal-free heterostructure photocatalyst PRGO/TP-COF for enhanced photocatalytic CO₂ reduction

The development of metal-free composite heterojunction catalysts is essential for economical and environmentally friendly carbon dioxide (CO2) conversion technologies. Most studies neglect the semiconductor property of graphene oxide (GO), which has the potential to participate in the construction of heterojunction catalysts. In this work, a novel organic-inorganic composite metal-free heterojunction photocatalyst was constructed for the photocatalytic CO2 reduction. Photo-reduced GO (PRGO) and sp(2)-carbon-chain triazine-based covalent organic framework (TP-COF) can be easily combined and form heterojunctions by a simple and green electrostatic self-assembly method through pi-pi interaction. The photogenerated electrons were transferred from the conduction band of PRGO to the valence band of TP-COF driven by energy band bending and built-in electric field, thus achieving effective charges separation. The strong reductive electrons on this S-scheme heterojunction efficiently and selectively reduced CO2 to CO. This work provides a new idea for designing GO-based heterojunction photocatalyst PRGO/TP-COF with potential application in CO2 photoreduction.