Synthesis of carbon nitride in-situ coupled tungsten oxide heterojunction with efficient photocatalytic redox properties

Herein, a heterogeneous photocatalyst of carbon nitride (CN) in-situ coupled tungsten oxide (WO3) were successfully prepared, which obtained by a one-step calcination treatment. The growth of WO3 nanorods on CN nanosheets increased the specific surface area and pore abundance of the material, resulting in the enhancement of the visible light absorption range of CN. The existence of oxygen vacancies in heterojunction can drive the transfer efficiency of photogenerated electrons from CN to WO3, which provides the effective separation of photogenerated carriers and in turn improves photocatalytic activity. The photocatalytic hydrogen production rate of CN-0.3 (in which 0.3 represents the addition amount of WCl6) was as high as 5.58 mmol/g/h, which reached 6.6-times higher than that of CN (0.85 mmol/g/h). In addition, the photocatalytic activity of CN-0.3 was still retained 81 % after five experiments of hydrogen production, indicating its stability and recyclability. Meanwhile, CN-0.3 has the highest photocatalytic reaction rate constant of 0.020 min−1 for degrading dye pollution at about 10-times higher rate compared with CN (0.002 min−1) and about 20-times higher than that of WO3 (0.001 min−1). CN-0.3 also has some degradation effect on antibiotics of TC and CIP, which improves the universality of photocatalyst in wastewater treatment. This work aims to offer viable and significant approaches for designing CN-based photocatalysts, hence enabling their efficient application in many photocatalytic domains.