Crystallinity-dependent photodegradation of metallic Bi in situ grown on perovskite Bi3TiNbO9 nanosheets toward antibiotic

Owing to its wide band gap of ~3.2 eV, perovskite Bi3TiNbO9 only absorbs the solar spectrum in the ultraviolet range, which restricts its use as an effective photocatalyst. Here, a controllable and facile reduction strategy was adopted to promote the in-situ growth of metallic Bi in perovskite Bi3TiNbO9 nanosheets. The in-situ growth of metallic Bi extended photoresponse to cover the whole visible region. Adsorption of tetracycline hydrochloride (TC-H) on the surface of Bi3TiNbO9 with in-situ growth of metallic Bi (BTNOOV-Bi0) was dramatically enhanced, while BTNOOV-Bi0 exhibited a superior photocatalytic performance for tetracycline hydrochloride (TC-H) degradation under visible light irradiation with the degradation rate of 5 times higher than that of pristine Bi3TiNbO9. Moreover, the degradation activity was strongly dependent on the crystallinity of metallic Bi phase in BTNOOV-Bi0 samples. On the basis of experiment results, the visible-light driven catalytic mechanism of BTNOOV-Bi0 was elucidated. Besides, the in-situ growth of metallic Bi was also introduced in perovskite Bi5FeTi3O15, resulting in an enhanced photocatalytic activity, which indicated an enormous potential of this strategy in semiconductor structure tuning. Our study provides an effective approach to boost the performance of photocatalysts for solar-energy conversion.