Construction of Z-scheme NH2-UiO-66/Bi2O2CO3 heterojunction with enhanced photocatalytic degradation of TC under visible light

In this work, a novel Z-scheme heterojunction NH2-UiO-66/Bi2O2CO3 (NU-X/BOC) composite photocatalysts were constructed by solvothermal method to degrade the tetracycline (TC) under visible light. The composites were characterized by XRD, FTIR, BET, XPS, PL, EIS, and so on. Results showed that the composite (NU-X/BOC) was successfully constructed through the loading of NH2-UiO-66 on Bi2O2CO3, which displayed a significant effect on TC removal. Especially, the highest TC degradation rate was 94.5% (NU-60/BOC) at pH 7, which was superior to the monomer NH2-UiO-66 (33%) and Bi2O2CO3 (40%). Electrochemical analysis showed that the good band-gap structure of the composites was conducive to improving the utilization rate of visible light, and promoting the separation of the photogenerated carrier, thus facilitating the degradation of TC. Moreover, radical trapping experiments and electron paramagnetic resonance (ESR) tests found the presence of active species (center dot O-2(-) and h(+)) played a dominant role. Based on the above results and characterization analysis, a potential Z-scheme heterojunction was put forth to describe the mechanism of electron transfer during the photocatalytic process. Cyclic experiments show that the material has good reusability. NU-X/BOC presented a new idea for the preparation of metal-organic skeleton-based photocatalytic materials.