Porphyrinic Based Hydrogen-Bonded Organic Framework/Tio Nanocomposites for Efficient Photocatalytic Degradation of Sulfadiazine

Porphyrinic hydrogen-bonded organic frameworks (porph-HOFs) have emerged as highly promising materials in the realm of photocatalysis owing to their remarkable attributes such as low density, high surface area, efficient visible light absorption and notable chemical stability, but the issue of photogenerated charge recombination persists as a significant concern. In this work, a porph-HOF composite material, namely PFC-72/TiO was designed, that is, TiO nanoparticles were bonded to the PFC-72 framework synthesized with cobalt porphyrin as organic ligand by introducing bridging molecules 4-mercaptopyridine (4-PySH). Furthermore, sulfadiazine (SDZ), as a highly prevalent antibiotic, was efficiently degraded from wastewater using PFC-72/TiO. The composite obtained demonstrates excellent dispersion of TiO and their intimate interaction with the porph-HOF matrix, resulting in an efficient photocatalytic performance attributed to their synergistic collaboration. Characterization and density functional theory further demonstrate that in PFC-72/TiO, TiO as an electron acceptor for efficient separation of photoexcited electron-hole pairs in PFC-72, leading to enhanced photocatalytic performance. In addition, due to the excellent acid-assisted crystalline redemption properties of PFC-72 and the axial coordination interaction with 4-PySH, PFC-72/TiO shows excellent stability and recyclability. Consequently, the optimal PFC-72/TiO exhibited a remarkable SDZ removal efficiency of 93.7% within 120 min, while maintaining an equivalent level of photoactivity even after undergoing 4 cycles. In summary, this work designed and synthesized a novel HOF-based photocatalyst with visible light response and high quantum yield, which is of great significance for the removal of antibiotics in water pollution.