Graphitic carbon nitride quantum dots seeding in MnTiO3 spheres: A novel visible light responsive photocatalyst with high interface charge transfer for antibiotic degradation

Abstract

As a promising heterojunction photocatalyst, MnTiO3 was incorporated with graphitic carbon nitride quantum dots (CNQDs) by performing a simple thermal method. The optimal sample MnTiO3@CNQDs(III) could degrade 93.1% of tetracycline, which was about 5.56 times than that of the pristine perovskite. This could be due to high light absorption ability, an appropriate band structure, enhanced separation rate of the photoinduced carrier species and the nitrogen-rich oxygen species content of CNQDs structure. The photocatalytic efficiency remained 78.9% in the seven cycle tests, indicating a considerable stable behavior. The main active substances were superoxide and holes as well as hydroxyl radicals slightly mediated the reaction. At neutral condition, the photocatalyst showed its best activity. After 60 min, the removal efficiency reached 100% by adding PMS while in the presence of H2O2 the highest removal obtained for 90 min. Different wastewater environments held a slight impact on photocatalytic efficiency to reveal a good applicability in real-world environments. Thus, the study presented a novel heterostructured semiconductor that includes the synergistic effect between CNQDs and MnTiO3, contributing to high photocatalytic activity.