Enhanced Visible-Light Performance of TiO2-Porphyrin Hybrids: A Synergistic Approach for Superior Acetaminophen Degradation

This study aimed to develop hybrid photocatalysts by anchoring 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (H₂​P) and its zinc complex (ZnP) onto commercial TiO₂​ (P25) using APTES as a molecular bridge to prevent porphyrin leaching. The functionalization process, confirmed by XPS and infrared spectroscopy, successfully established a stable monolayer that addressed the lixiviation issues observed in previous non-bridged systems. Results showed that the TiO_2​-APTES-H₂​P and TiO_2​-APTES-ZnP hybrids achieved approximately 40% acetaminophen degradation under white LED radiation within 60 minutes. This performance represents a 3.3-fold increase in photocatalytic activity compared to unmodified TiO₂​ (P25). Additionally, the immobilized porphyrins demonstrated a 4 to 8-fold increase in photoactivity over their homogeneous counterparts. These findings indicate that the APTES-mediated immobilization effectively enhances light harvesting and charge transfer.