This study investigates the stability and optimization of spray-coated \(TiO_2\) thin films synthesized via a reverse micelle sol–gel method. This approach enabled the deposition of thin films onto curved and rough surfaces with excellent adhesion. Films were calcined at 300 \(^{\circ }\) C, 400 \(^{\circ }\) C, 500 \(^{\circ }\) C, and 600 \(^{\circ }\) C, and their structural, morphological, and photocatalytic properties were analyzed. Calcination at 600 \(^{\circ }\) C yielded the best results, with enhanced anatase crystallinity, increased surface roughness, and improved photocatalytic performance. Under UV light, the films achieved nearly complete degradation of methylene blue (MB) within 4 h. Electrical characterization revealed that the optimized calcination temperature reduced the energy band gap and improved electron–hole pair generation efficiency. These findings emphasize the critical role of calcination in enhancing the photocatalytic properties of \(TiO_2\) thin films, offering a sustainable and effective method for water pollutant treatment.
