Synthesis and Characterization of MIL-100(Fe) Metal-Organic Framework on Titania as Visible Light-Active Photocatalyst for Bisphenol A Degradation

Titania (TiO2) is a widely utilized metal oxide nanomaterial used for pollutant degradation, yet its limited activity under visible light restricts its broader photocatalytic applications. In this study, TiO2 was incorporated with a metal-organic framework, MIL-100(Fe), via the hydrothermal method forming MIL-100(Fe)/TiO2 composites. This study also investigated the impact of different amounts of TiO2 in MIL-100(Fe)/TiO2 composites. The structural and optical properties of the synthesized composites were characterized using various techniques. X-ray diffraction (XRD) confirmed the presence of both anatase and rutile TiO2 phases, while Fourier transform infrared (FTIR) spectroscopy validated the key functional groups. Ultraviolet-visible near-infrared (UV-Vis-NIR) spectroscopy revealed that MIL-100(Fe)/TiO2 composites with 5.4 mmol of TiO2 (MIL-100(Fe)/TiO2 (5.4)) exhibited a reduced bandgap of 1.70 eV, compared to 2.10 eV for MIL-100(Fe)/TiO2 composites with 1.8 mmol of TiO2 (MIL-100(Fe)/TiO2 (1.8)), enhancing visible-light absorption. Field emission scanning electron microscopy (FESEM) showed a size distribution of 74.7 – 99.1 nm. Photocatalytic activity of the synthesized MIL-100(Fe)/TiO2 composites was evaluated through bisphenol A (BPA) degradation under UV light irradiation initially. Notably, the synthesized MIL-100(Fe)/TiO2 (5.4) exhibited the highest photocatalytic activity (81.43%), while MIL-100(Fe)/TiO2 (1.8) showed the lowest efficiency (36.36%). Given the improved visible-light absorption from the reduced bandgap, further evaluation under visible-light conditions was conducted. The results revealed that MIL-100(Fe)/TiO2 (5.4) achieved significant degradation (69.49%), whereas commercial TiO2 exhibited no activity (0%). These findings confirm that MIL-100(Fe)/TiO2 composites enhance visible-light-driven photocatalysis by extending light absorption and improving charge separation, thereby reducing electron-hole recombination for effective environmental remediation.