3-D hierarchical micro/nano-structures of porous Bi2WO6: Controlled hydrothermal synthesis and enhanced photocatalytic performances

As one of the simplest aurivillius layered materials, Bi2WO6 is a promising photocatalyst with a wide range of applications. The construction of 3-D hierarchical micro/nano-structures (3-D HMNSs) can be considered as an excellent strategy to improve the photocatalytic activity. In this paper, a series of porous Bi2WO6 photocatalysts with 3-D HMNSs were synthesized by hydrothermal method via adjusting the concentration of reactants. All kinds of characterization methods (XRD, SEM, TEM, BET, UV–Vis, etc.) were used to characterize the as-synthesized samples. Taking tetracycline as a model pollutant, the photocatalytic properties of these Bi2WO6 photocatalysts were investigated, and the mechanism of its photocatalytic degradation was also proposed. The Bi2WO6-4# sample showed the highest visible-light photocatalytic activity, with tetracycline removal rate of 99.9% in 1 h irradiation and a kinetic reaction rate constant of 0.06071 min−1. The catalytic mechanism analysis shows that the active radicals of ·OH and ·O2− produced by the photoelectron hole have strong oxidizing property, which can quickly decompose tetracycline. Bi2WO6-4# with oriented arrangement of nanocrystals and increased Eg have the advantage of promoting the separation of electron-hole pair, accounting for the high photocatalytic activity.