Rapid calcination unlocks superior solar photocatalysis of Bi12TiO20 ceramics

This work demonstrates the effectiveness of rapid solid-state calcination to synthesize sillenite-type Bi12TiO20 with superior solar photocatalytic activity. Stoichiometric mixtures of Bi2O3 and TiO2 were calcined at 500–800 °C for 3–240 min to evaluate the effect of thermal treatment on phase formation, microstructure, and optical properties. XRD and SEM confirmed that a pure Bi12TiO20 phase forms completely at 800 °C after only 3 min. Although all samples at this temperature were phase pure, prolonged calcination produced subtle variations in lattice parameters and band gap, revealing a strong influence of dwell time on structural and electronic properties. In Rhodamine B degradation under sunlight, the 3 min sample showed the highest activity, achieving 85% removal in 60 min and outperforming commercial anatase TiO2. This enhanced efficiency arises from a favorable density of oxygen vacancies that promote charge carrier separation and reactive oxygen species generation, enabling a rapid, energy-efficient route to high-performance photocatalysts.