Photocatalytic Activity of Room Temperature Prepared Sol-Gel Spin-Coated Anorthic Magnéli Phase (Ti 4 O 7 ) Thin Films

Substoichiometric titanium oxides, particularly M agnéli phases (TinO2n–1, n=3-10), exhibit promising properties for various functional applications. However, achieving high-quality M agnéli phase (Ti4O7) thin films at room temperature remains a significant challenge due to limitations in conventional deposition techniques. In this study, we report the successful room temperature fabrication of pure Ti4O7 thin films on glass substrates using a sol-gel spin coating approach. Structural, optical, morphological, elemental, luminescence and photocatalytic properties of the films were systematically investigated by varying precursor concentrations (1 and 4 mmol). Structural analysis confirmed the formation of anorthic crystal structure of Ti4O7 without any secondary phase. Optical studies revealed bandgap variations (2.08 and 3.75 eV) attributed to differences in film thickness. Photocatalytic performance, assessed through methylene blue dye degradation under visible light, demonstrated enhanced activity for the 1 mmol film, achieving a degradation efficiency of 72% and a rate constant of 3.3036 × 10–3 min–1. This work offers a feasible chemical solution sol-gel technique to overcome room temperature deposition limitations of M agnéli phases, and opening new possibilities for their integration into photocatalytic and optoelectronic applications.