Modified surficial chemistry micro-circumstance and mid-gap effect on photocatalytic ability of tetracycline by introducing of nitrogen in Fe2(MoO4)3

Abstract

A novel non-metal doped Fe2(MoO4)3 photocatalyst with flower-like microstructure was synthesized by a hydrothermal method. The incorporation location of nitrogen was proved by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). UV–Vis diffuse reflectance spectroscopy (DRS) revealed mid-gap from the dope of nitrogen strongly enhanced the visible-light absorption ability. Scanning electron microscopy (SEM) showed that the morphology of doped samples was greatly influenced by nitrogen dopant. Significantly, N-doped Fe2(MoO4)3 exhibits an ideal tetracycline (TC) photocatalytic ability, which can be a potential function material for antibiotics degradation. Photoluminescence (PL) and photocurrent indicated that constract of oxygen vacancy, which modified the surficial chemistry micro-circumstance, greatly depressed the recombination rate of the photo-generated electron–hole pairs. In order to investigate the possible mechanism of promoted TC degradation efficiency, radical trapping experiments of pure Fe2(MoO4)3 and N-doped samples were examined. It was found that superoxide radicals (·O2−) and hydroxyl radical (·OH) formed in the visible light excitation process play an important role in the fragmentation reaction. Moreover, the possible ring-opening intermediates were deduced and a reasonable enhancement mechanism of N-doped Fe2(MoO4)3 TC degradation was also investigated in this study. This investigation could provide an effective reference for doping non-metallic species for improving the photocatalytic activity of Fe2(MoO4)3.