Flexoelectricity enhanced photocatalysis in Bi4Ti3O12 for binary dye degradation

Bismuth titanate (Bi4Ti3O12, BTO) was prepared via the solid-state reaction route. Flexoelectricity was induced in the powder sample through rapid cooling to room temperature (350–20 °C) to produce the thermally strained BTO (FBTO) sample. The as-synthesized and thermally treated (quenched) samples were examined using x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy. The catalytic degradation performance of these catalysts was evaluated by degrading methylene blue (MB), methyl violet (MV), and a binary mixture of these two dyes in the photocatalysis process. Specifically, the FBTO sample showed an enhanced degradation of 52% for MB dye and 77% for MV dye, outperforming the BTO sample, which showed a degradation of 40% for MB dye and 68% for MV dye. A similar enhancement in degradation performance was also noticed for the binary dye. Furthermore, the role of various parameters, such as pH, light intensity, and catalyst dosage, on the flexo-photocatalytic degradation of MB dye was investigated. Among these parameters, pH played a significant role in determining the dye degradation performance. The results indicate that MB dye degradation was significantly suppressed in an acidic medium (pH ∼ 4), whereas higher degradation performance was observed in neutral (pH ∼ 7) and alkaline (pH ∼ 10) conditions. These findings highlight the potential of flexoelectricity as a strategy to improve catalytic performance in environmental remediation applications.