Fabrication of bismuth titanate nanosheets with tunable crystal facets for photocatalytic degradation of antibiotic

The synergism between different surface facets of semiconductor with optimal ratios can contribute to obtain enhanced photocatalytic degradation performance. Herein, a bismuth-based material Bi4Ti3O12 exposed with {001} top facets and {010}/{100} lateral facets was prepared by the molten-salt method. More importantly, the ratio of different exposed facets could be controlled by adjusting the synthesis temperature of molten-salt synthesis process. The as-prepared Bi4Ti3O12 exposed with the optimal ratio of {001} top facets to {010}/{100} lateral facets exhibited the enhanced degradation activity of tetracycline hydrochloride (TC-HCl) under irradiation. The rate constant of optimal sample reached 0.904% min−1, over 3.3 times as compared with that of the counterpart with higher proportion of {001} facets. Besides, active species trapping experiments, photoelectrochemical measurements and selective photodeposition tests were used to illuminate the photocatalytic degradation mechanism. According to that, the enhanced degradation activity could be ascribed to crystal facet synergism which can promote photoinduced carrier separation. This work can give insights into designing and constructing other two-dimensional (2D) bismuth-based materials with the aim of enhancing photocatalytic degradation performance.