摘要 : Z-scheme heterostructure of nitrogen-vacancy rich g-C3N4 nanoparticles (V-N-CN) confined in oxygen-vacancy rich TiO2 nanotube arrays (V-O-TiO2) were fabricated to enhance CO2 photoreduction under visible light irradiation. Dual va... 展开 Z-scheme heterostructure of nitrogen-vacancy rich g-C3N4 nanoparticles (V-N-CN) confined in oxygen-vacancy rich TiO2 nanotube arrays (V-O-TiO2) were fabricated to enhance CO2 photoreduction under visible light irradiation. Dual vacancies mediated V-N-CN/V-O-TiO2 heterostructure exhibits excellent photocatalytic CO2 reduction performance, and the CO and CH4 evolution rate are about 1.5 times and 3 times higher than that of pristine CN/TiO2, respectively. Possible reasons for the improvement of photocatalytic activity are as follows: (1) the adsorption and activation capacity of CO2 on the surface of CN/TiO2 are obviously improved due to the construction of nitrogen and oxygen dual vacancies; (2) the construction of dual vacancies are beneficial for enhancing the visible light absorption, promoting separation and transfer of photogenerated carriers due to intimate contact interface between V-N-CN and V-O-TiO2; (3) Z-scheme heterostructure could boost oxidation ability of V-N-CN/V-O-TiO2 and promote the production of more hydroxyl radical, which can react with CO2 to form HCO3-, leading to a new pathway to CO2 photoreduction compared to pristine CN/TiO2. 收起