Synthesis and Characterization of C, N Co-Doped Tio₂ Nanoparticles Using Chicken Egg White and Their Use in the Degradation of Benzoic Acid in the Visible Spectrum

Introduction: Titanium dioxide (TiO2) has long been regarded as the perfect nano-material because of its great stability, affordability, and non-toxicity, which make it safe for use by humans and the environment. TiO2's broad band gap limits its use in photocatalysis under visible light. When non-metallic elements are added to the TiO₂ lattice, new energy levels above the TiO2 valence band are introduced, which reduces the band gap energy and increases its photocatalytic activity in the visible part of the light spectrum. Method: In this work, a single-step sol-gel method is used to prepare C,N-doped TiO2 nanoparticles using chicken egg white as a precursor for both carbon and nitrogen. The prepared nanoparticles were used to degrade benzoic acid, which is considered an emerging pollutant in wastewater. The degradation of benzoic acid was carried out using three different light sources: UV-C light, solar light, and visible light. Result: Characterization techniques such as X-ray diffraction, Ultraviolet-visible diffuse reflectance spectroscopy, Scanning Electron Microscopy with Energy Dispersive X-ray analysis, and Trans-mission Electron Microscopy with Selected Area Electron Diffraction confirm the presence of car-bon and nitrogen in TiO2 nanoparticles, with sizes ranging between 13 and 15 nm. XRD confirms the presence of the anatase phase of TiO2 nanoparticles, which is crystalline in nature. Discussion: Using a green sol-gel method with chicken egg white as a dual source of carbon and nitrogen, C, N-doped TiO2 nanoparticles were successfully synthesized. The characterization con-firmed the anatase phase with particle sizes ranging from 13 to 15 nm and effective dopant incorpo-ration, which narrowed the band gap and improved visible-light absorption. Compared to undoped TiO₂, the photocatalytic activity of the doped TiO2 showed significant enhancement in degrading benzoic acid under visible and solar light. This improvement is credited to the formation of mid-gap states that foster improved charge separation and light utilization. The research illustrates a hopeful method for treating wastewater through sunlight-driven photocatalysis. Conclusion: A degradation study of benzoic acid was carried out with TiO2 P-25, which degraded only 5% in the visible region, while C,N-doped TiO2 degraded benzoic acid up to 45% under visible light, which was further enhanced by 10–12% with the addition of H₂O₂, thus indicating the narrow-ing of the TiO2 band gap and increased photocatalytic activity in the visible part of the light spec-trum. The kinetics of all the reactions followed pseudo-first-order behavior. conclusion: Degradation study of benzoic acid was carried out with TiO2 P-25 which was only 5 % in visible region while C,N-doped TiO2 degraded benzoic acid up to 45 % in visible light which was again enhanced 10 – 12 % by addition of H2O2. Thus, indicating narrowing of TiO2 band gap and increasing its photocatalytic activity towards visible part of light spectrum. The kinetics of all the reactions follow pseudo-first-order