Synthesis of TiO2/Bi-MOFs composites with excellent performance for enhanced visible-light driven photocatalytic activity to remove organic contaminants

Nowadays, more and more regions of the earth are facing energy crisis and environmental pollution issues. Photocatalytic technology converts solar energy into chemical energy in an environmentally friendly way, which is considered as an effective method to solve such issues. In this work, a series of TiO2/Bi-MOFs (TiO2/Bismuth based metal-organic frameworks) composites were successfully prepared by a simple one-pot solvothermal method, and the photocatalytic activity of the composites was evaluated by photocatalytic degradation of rhodamine B (RhB) dye under visible light, and the catalytic activities of the samples were also investigated for methyl orange (MO), methylene blue (MB) and tetracycline (TC). The samples were characterized by using various analytical techniques. The composites exhibited better catalytic properties compared with the original single component, which was attributed to the high dispersion of TiO2 and the synergistic effect of efficient interfacial charge transfer between TiO2 and Bi-BTC (BTC: benzene-1,3,5-tricarboxylate, Scheme 1). Among the results, the photocatalytic degradation efficiencies of 25-T/B (T/B, TiO2/Bi-BTC: TiO2/bismuth homobenzotrizoate composites), 35-T/D (T/D, TiO2/Bi-BDC: TiO2/bismuth terephthalate composites) and 25-T/P (T/P, TiO2/Bi-BPDC: TiO2/bismuth biphenyldicarboxylate composites) for RhB were all 99% after 40 min of visible light irradiation. Furthermore, the degradation efficiency of 25-T/B for RhB could maintain high catalytic activity after five cycles, indicating the high stability of the catalyst. Overall, the materials presented in this work are a series of reusable, high catalytic activity and economical photocatalysts for water purification, and the effects of different ligands on the photocatalytic activity of TiO2/Bi-MOFs composites were investigated.