Hierarchical architectures of bismuth molybdate nanosheets onto nickel titanate nanofibers: Facile synthesis and efficient photocatalytic removal of tetracycline hydrochloride.

A huge challenge in the field of pollutant removal is the scarcity of visible-light-driven (VLD) photocatalysts that are efficient, stable, easily recyclable and capable of mineralizing organic pollutants. In this regard, a novel hierarchical architecture of Bi2 MoO6 nanosheets onto NiTiO3 nanofibers for tetracycline hydrochloride (TC) removal was rationally designed and fabricated via a facile approach. In this heterojunction system, highly homogeneous-distributed Bi2 MoO6 nanosheets were anchored on electrospun NiTiO3 nanofibers, endowing the heterojunction with compact interfacial contact. By virtue of the favorable interfacial contact and matched band alignment, promoted suppression of photo-generated electron-hole recombination is achieved in Bi2 MoO6 /NiTiO3 system, as confirmed by photoluminescence measurement. As a result, the heterojunction with Bi2 MoO6 /NiTiO3 molar ratio of 1:1 exhibits an outstanding VLD photocatalytic activity and good stability for tetracycline hydrochloride (TC) degradation. The photodegradation rate constant (k) is 26.0, 5.4 or 3.7 folds higher than that of pristine NiTiO3 , Bi2 MoO6 , or the mechanical mixture (20.2 wt% NiTiO3  + 79.8 wt% Bi2 MoO6 ). The holes and superoxide radicals are detected as the dominant active species responsible for TC removal. Moreover, this work reports an efficient VLD photocatalyst for TC removal and will open up new insights into the design of novel fiber-shaped VLD heterojunction photocatalyts for environment remediation.