Construction of Z-scheme g-C3N4/Ag/P3HT heterojunction for enhanced visible-light photocatalytic degradation of tetracycline (TC) and methyl orange (MO)

Constructing a conductive interface is crucial for the transfer of photoexcited charges in the photocatalytic heterojunction system. In this study, we introduced Ag into g-C3N4/P3HT system to construct a conductive interface which benefits for transfer of photoexcited charges between g-C3N4 and P3HT. A series of characterizations were employed to investigate the chemical structure, morphology and optical property of the obtained catalysts. And the photocatalytic activity of the as-prepared g-C3N4/Ag/P3HT composites were evaluated by the degradation of tetracycline (TC) and methyl orange (MO) aqueous solution under visible light irradiation. Results show that the g-C3N4/Ag/P3HT exhibits a broad absorption band in the region of 400-700 nm and the photocatalytic activity of g-C3N4/Ag/P3HT obtains a great improvement comparing with that of g-C3N4, g-C3N4/Ag and g-C3N4/P3HT. In addition, the optimized loading content of P3HT is 0.3 mass% based on g-C3N4. The enhanced photocatalytic performance is due to the introduction of Ag, which improves the transfer of photoexcited charges between g-C3N4 and P3HT. The active species trapping experiment shows that the main active specie is center dot O2-. After five recycling experiments, the g-C3N4/Ag/P3HT shows high stability in the photocatalytic performance.