Ionic Liquid Mediated Sol Gel Method for Fabrication of Nanostructured Cerium and Phosphorus Doped TiO2 - A Benign Photocatalyst: Diversified Applications in Degradation of Dyes and Microbes.

This work aims to produce semiconductor nanoparticles capable of harnessing visible light for the degradation of dyes and microbes. Employing an ionic liquid-assisted sol-gel process with varying dopant weight percentages, the study focuses on crafting Cerium (Ce) and Phosphorus (P) doped TiO₂ Nanomaterials. Structural assessments, including Powder X-ray Diffraction (confirming the anatase phase), Transmission Electron Microscopy (revealing a particle size of 6.2 nm), Brunauer-Emmett-Teller surface area analysis (yielding 166 m²/gr), and Scanning Electron Microscopy (examining the morphology), were conducted. The catalysts were further evaluated for optical characteristics: UV-vis diffuse reflectance spectrum (indicating an energy gap of 2.59 eV), Electrochemical Impedance Spectroscopy (with an E_fb of -0.30 V), and Valence band XPS (showing E_vb at 2.03 eV). Substitutional doping of dopants into the TiO₂ lattice was confirmed through X-ray photoelectron spectroscopy and Fourier Transform Infra-Red analysis. Photoluminescence Spectrum and Time Correlated Single Photon Counting analysis was employed to investigate electron-hole recombination. These characterizations suggest the catalysts are effective in degrading microorganisms and dyes under visible light exposure. Optimal conditions were obtained using CPT5IL2 at pH 3, 0.10 g catalyst dosage, and an initial dye concentration of 10 mg/L, which were determined to achieve complete dye degradation within 60 min. Furthermore, the catalyst's antibacterial and antifungal activity against Enterobacter aerogenes (MTCC-241, Gram-negative), Salmonella typhimurium (MTCC-98, Gram-negative), and Candida albicans (MTCC-277) were studied.