Fabrication of novel CoO/porous graphitic carbon nitride S-scheme heterojunction for efficient CO2 photoreduction

The construction of heterojunction plays a key role in solving the charge separation and transfer at the interface of photocatalyst. Herein, a new type of step-scheme (S-scheme) heterojunction was formed by growing cobalt oxide (CoO) in situ on porous graphitic carbon nitride (PCN) to convert CO2 to CO. The porous structure of PCN can increase the absorption of CO2 and act as an active site. The special charge separation of S-scheme heterojunction can give CoO/PCN system with strong redox ability. And S-scheme heterojunction can accelerate charge separation and transfer at the interface. Compared with CoO and PCN, CoO/PCN composites exhibits a higher CO2 reduction rate (40.31 μmol g-1h−1), 3.43 and 23.85 times higher than that of CoO (11.73 μmol g-1h−1) and PCN (1.69 μmol g-1h−1), respectively.