Synthesis of novel g-C₃N₄/CaTiO₃/CQDs heterojunction photocatalyst with enhanced visible light photocatalytic performance

In this paper, a high-efficient visible light responsive g-C3N4/CaTiO3/CQDs Z-type heterojunction photocatalyst was successfully prepared by a two-step method for the photodegradation of organic pollutants in water. The combination of g-C3N4, CaTiO3 and CQDs could produce synergistic effect, which facilitated the separation of carriers, thereby enhancing photocatalytic activity. The photocatalytic kinetic removal rate of g-C3N4/CaTiO3/ CQDs for methylene blue could reach about 8 times of g-C3N4 and 5.5 times higher than that of CaTiO3. The effects of co-existing ions, initial pH, water source, and humic acid on meloxicam degradation were examined. Repeatability experiments indicated that the composite had good reusability and stability with 81.1 % removal for meloxicam after four cycles. The main active substances of g-C3N4/CaTiO3/CQDs in free radical capture experiment was center dot O-2(-center dot). Possible degradation pathways of meloxicam were also analyzed. The results highlight the g-C3N4/CaTiO3/CQDs Z-type heterojunction is a desirable photocatalyst for removing organic pollutants in water.