Supramolecular self-assemble deficient carbon nitride nanotubes for efficient photocatalytic CO₂ reduction

Carbon nitride is an attractive non-metallic photocatalyst due to its small surface area, rapid electron-hole recombination, and low absorption of visible light. In this study, one-dimensional carbon nitride nanotubes were successfully synthesized by supramolecular self-assembly method for photocatalytic reduction of CO₂ under mild conditions. The material demonstrates significantly improved CO₂-to-CO activity compared to bulk carbon nitride under visible light irradiation, with a rate of 12.58 μmol g^-1h^-1, which is 3.37 times higher than that of pristine carbon nitride. This enhanced activity can be attributed to the abundant oxygen defects and nitrogen vacancies in the unique tubular carbon nitride structure, which results in the generation of more active sites and the efficient acceleration of the migration of photogenerated electron-hole pairs. Various characterizations collectively support the presence of these defects and vacancies. Moreover, in situ DRIFTS spectroscopy supported the proposed reaction mechanism for the photoreduction of CO₂. This eco-friendly design approach provides novel insights into utilizing solar energy for the production of value-added products.