Photoluminescence of Oxygen Vacancy-Rich Nano-Tio2 Photocatalyst for Methylene Blue Color Degradation

Abstract

One of the biggest environmental concerns is the contamination of wastewater by synthetic dyes. Despite being a photocatalyst, TiO2's efficacy is limited by its poor absorption of visible light. By using solvothermal synthesis at 150°C, 180°C, and 210°C to engineer oxygen vacancies (OV), this study improves the performance of TiO2. Temperature-induced increases in crystallinity and OV were confirmed by XRD, EDS, PL, and XPS analyses. T150 outperformed TiO2 P25 in photocatalytic efficiency, breaking down 93.43% of MB in 3 hours in the sun. Since an ideal OV concentration reduced band gap energy, improved charge carrier separation, and increased reactive oxygen species generation, it is believed to be the cause of the increased activity. Analysis of photoluminescence showed mid-gap states that improve absorption of visible light. This study clarifies the connection between photoluminescence and photocatalysis and demonstrates that OV engineering is a promising strategy for high-efficiency TiO2-based wastewater treatment.

Keywords: oxygen vacancies, Photocatalysis, TiO2, Methylene blue, visible-light absorption, oxygen species