Preparation and Photocatalytic Performance of Modified Hydrotalcite

MG-Al hydrotalcite (MgAl-LDH) was prepared by hydrothermal method, and MgAl-LDH was modified with bismuth oxycarbonate (Bi₂O₂CO₃) in order to obtain Bi₂O₂CO₃/MgAl-LDH composite photocatalytic material. The composition, morphology and band gap of the prepared samples were characterized by XRD, SEM and UV-VIS diffuse reflection. The degradation ability of Bi₂O₂CO₃/MgAl-LDH composite photocatalytic material was tested by degradation methylene blue solution (MB) under natural light. Results: When the modification amount of Bi₂O₂CO₃ was 10%, the photocatalytic performance of the complex was the best, and the degradation rate of MB was as high as 92% in 2 h under natural light (tungsten halogen lamp). The quenching experiments showed that the main active species involved in the degradation of MB were superoxide free radicals (•O₂-). Cyclic tests show that the composite photocatalyst still has a certain photocatalytic degradation ability after 5 cycles. Finally, the charge transfer process and mechanism of Bi₂O₂CO₃/MgAl-LDH were investigated by using the experimental data and characterization results.