Enhanced visible-light catalytic degradation of methylene blue by improving adsorption of porous zirconium-based porphyrin MOFs sensitized TiO_2 photocatalyst

摘要

The zirconium-based porphyrin MOFs sensitized TiO_2 (PCN224-TiO_2) was synthesized in situ by self-assembly of porphyrin, ZrCl_4 with nano TiO_2. The composite catalyst was determined by detailed structural and photoelectrochemical characterization. The UV-Vis absorption and fluorescence spectrum confirm that PCN224 and TiO_2 are coupled. The PCN224-TiO_2 had significant absorption of visible light and the PCN224-TiO_2 had the largest photo-generated current, which proved the porphyrin MOFs material has good internal conductivity and has a close combination with TiO_2. Compared with carboxyphenyl porphyrin sensitized TiO_2 (HTCPP-TiO_2), mixture of TCPP and TiO_2 (TCPP/TiO_2) and PCN224, the PCN224-TiO_2 showed better removal performance of methylene blue under visible light. Under low-power xenon lamp irradiation, the removal rate of PCN224-TiO_2 (1∶3) on methylene blue reached 93.2% in 4 h. And PCN224-TiO_2 had stable cycling catalytic performance. The PCN224-TiO_2 promoted the degradation process by strengthening the adsorption of organic pollutants, thus improving the removal performance.