Influence of temperature and reaction time on photocatalytic performance of BaTiO3 nanoparticles for organic pollutant degradation in aqueous environment

Developing low-cost, high-performance photocatalysts is crucial for advancing photocatalytic technologies in organic wastewater treatment. In this study, barium titanate (BaTiO₃) nanoparticles were synthesized via a hydrothermal method followed by calcination at 600 °C and evaluated for their photocatalytic activity toward the degradation of cationic and anionic dyes such as methylene blue (MB) and methyl orange (MO). The effects of hydrothermal temperature and reaction time on phase composition, crystallinity, morphology, and optical properties were systematically investigated. All synthesized samples exhibited a cubic BaTiO₃ phase, with varying levels of BaCO₃ impurities. Elemental analysis revealed near-stoichiometric Ba:Ti ratios at 135 °C and 150 °C, while Ba enrichment was observed at 175 °C. The optimal sample, synthesized at 150 °C for 48 h, featured a mixed morphology of nanoparticles and nanorods, a band gap of 3.02 eV, and high crystallinity, achieving degradation efficiencies of 93 % (MB) and 43 % (MO) with rate constants of 0.214 and 0.023 min^–1 g^–1, respectively. Scavenger experiments identified photogenerated holes (h⁺) as the dominant reactive species, with superoxide radicals (^•O₂^–) playing a secondary role. The selectivity toward MB over MO was attributed to favorable electrostatic interactions between the catalyst surface and the cationic dye. Control experiments confirmed the photocatalytic nature of the degradation process. This work highlights the importance of controlling synthesis parameters and phase purity to enhance BaTiO₃ photocatalytic performance and provides insight for designing efficient materials for environmental remediation.