One-dimensional rod-shaped Ag2Mo2O7/BiOI n-n junctions for efficient photodegradation of tetracycline and rhodamine B under visible light

Abstract

One-dimensional rod-shaped Ag 2 Mo 2 O 7 /BiOI composite photocatalysts were prepared via a facile hydrothermal-calcining method. The structure, morphologies, and elemental nature of the photocatalysts were characterized. Ag 2 Mo 2 O 7 /BiOI was formed through the attachment of BiOI nanosheets on the surface of Ag 2 Mo 2 O 7 rods, resulting in a 1D/2D heterojunction with larger interface area, more surface-active sites, and faster charge transfer channel. The Ag 2 Mo 2 O 7 /BiOI heterogeneous exhibited excellent and stable photodegradation performances for Rhodamine B (RhB) and Tetracycline (TC) under visible light irradiation. At the optimum composition of 15 wt% BiOI, the Ag 2 Mo 2 O 7 /BiOI heterojunction exhibited a highest degradation rate for RhB and TC, which were 70 times and 16 times higher than those of Ag 2 Mo 2 O 7 , respectively. The improved photocatalytic performance can be attribute to the efficient separation of photoinduced charges caused by the formation of the n-n heterojunction between Ag 2 Mo 2 O 7 and BiOI. Additionally, the dominant active species of photocatalytic reaction were determined to be • O 2 − and h + by free radical capture experiments and ESR test. In addition, a toxicity test with E. coli was carried out, which shows that the photodegraded Tetracycline solution is basically harmless to E. coli. Based on the experimental results and hybrid density functional theory calculation, a plausible photocatalytic mechanism of n-n heterojunction was proposed. • One-dimensional rod-shaped Ag 2 Mo 2 O 7 /BiOI were synthesized by a solvothermal method. • Ag 2 Mo 2 O 7 /BiOI can efficiently degrade Tetracycline. • The toxicity of the degraded tetracycline solution was low by E. coli activity detection. • Charge carriers were separated due to the n-n heterojunction and large interface area.