Influence of combustion temperature on TiO2 photocatalysis for the degradation of persistent organic pollutants

TiO₂ photocatalysts were synthesized at 220–900 °C using a pilot-scale combustion reaction to investigate the influence of crystalline structure on the degradation of Crystal Violet (CV) and Methyl Orange (MO). XRD revealed amorphous, anatase, mixed anatase–rutile, and rutile phases. FTIR confirmed characteristic lattice vibrations, and SEM showed agglomerated plate-like particles with significant growth at higher temperatures. The BET surface area dropped from 63.2 m 2 g −1 (350 °C) to 0.671 m 2 g −1 (900 °C). The band gap narrowed from 3.14 to 2.67 eV with increasing temperature. Photocatalytic tests demonstrated that amorphous TiO₂ exhibited the highest CV degradation (89.91%) under 60 min UV irradiation, whereas none of the samples degraded MO due to electrostatic repulsion between the anionic dye and negatively charged TiO₂ surfaces. The results confirm the strong dependence of photocatalytic performance on combustion temperature and phase composition, and support the scalability of this synthesis route.