Integrating N and F co-doped TiO2 nanotubes with ZIF-8 as photoelectrode for enhanced photo-electrocatalytic degradation of sulfamethazine

Traditional photoanodes decreased in mass transfer rate via coating powdered catalysts on conductive glass. In this work, we obtained a visible light-driven semiconductor- metal organic frameworks (MOFs) hybrid photoelectrode, which was constructed by electro-anodization and deposition growth process. The ZIF-8/NF-TiO2 photoelectrode was based on hollow TiO2 nanotubes, and ZIF-8 nanoparticles were deposited on the surface of the pyramid-shaped rutile TiO2 substrate after N and F co-doping. Compared with unmodified anatase TiO2, the reaction rate of ZIF-8/NF-TiO2 increased by 21.7 times, and the synergistic factor in the photo-electrocatalytic process could reach to 3.5. The porous structure of ZIF-8, the intrinsic band difference between anatase and rutile TiO2 greatly improved light utilization, and promoted electron–hole separation. The electrode could be easily recycled and exhibit excellent repeatability, and the degradation efficiency almost unchanged after 8 cycles. Moreover, possible degradation pathways and photo-electrocatalytic degradation mechanisms of sulfamethazine were proposed. This progress could bring novel insights for the design of semiconductor-MOFs hybrid photo-electrocatalysts.