Photogenerated electron transfer channels in carbon nanotube-intercalated Cu2O nanospheres for boosting visible light-driven CO2 reduction

Herein, a carbon nanotubes-intercalated oxygen vacancy-rich Cu2O hollow nanosphere (Cu2O-Vo-CNTs) photocatalyst was fabricated by the in-situ low-temperature water bath method. The atomic-level interface between the π-conjugation electron shell of CNTs and Cu2O nanosphere can induce the formation of an efficient electron transfer channels, and the photogenerated electron originated from the conduction band of Cu2O can migrate and gather from the interior of the catalyst to its surface via the electron transfer channel, which is beneficial to improve the separation efficiency of photogenerated electron-hole pairs. Among the catalysts, Cu2O-Vo-CNTs-5 catalyst exhibits the highest photocatalytic activity during visible light-driven CO2 reduction with H2O, i.e., its formation rate and selectivity of CO gas-phase product is 60.25 μmol g−1 h−1 (8-fold of Cu2O) and close to 100%, respectively. Based on the results of ex/in-situ physicochemical characterizations and density functional theory calculation, the mechanism for photocatalytic CO2 reduction is proposed: Surface photogenerated electron via the directional migration channels can boost the key step of *CO2-to-*COOH for enhancing the generation of CO product. This work offers a valuable insight to develop high-efficient CO2 photoreduction photocatalyst.