Preparation, Property Characterization of Gd2YSbO7/ZnBiNbO5 Heterojunction Photocatalyst for Photocatalytic Degradation of Benzotriazole under Visible Light Irradiation

Abstract

The Gd2YSbO7/ZnBiNbO5 heterojunction photocatalyst was synthesized for the first time by the facile in situ precipitation method. The structural properties of a Gd2YSbO7/ZnBiNbO5 heterojunction photocatalyst were characterized by X-ray diffractometer, scanning electron microscope-X ray energy dispersive spectra, X-ray photoelectron spectrograph and UV-Vis diffuse reflectance spectrophotometer. The band gap energy (BGE) of Gd2YSbO7 or ZnBiNbO5 was found to be 2.396 eV or 2.696 eV, respectively. The photocatalytic property of Gd2YSbO7 or ZnBiNbO5 or Gd2YSbO7/ZnBiNbO5 heterojunction photocatalyst (GZHP) was reported. After a visible-light irradiation of 145 minutes (VLI-145 min), the removal rate (RER) of benzotriazole reached 99.05%, 82.45%, 78.23% or 47.30% with Gd2YSbO7/ZnBiNbO5 heterojunction (GZH), Gd2YSbO7, ZnBiNbO5 or N-doped TiO2 (NTO) as photocatalyst. In addition, the kinetic constant k, derived from the dynamic curve toward benzotriazole concentration and visible light irradiation time with GZH as a photocatalyst, reached 0.0213 min−1. Compared with Gd2YSbO7 or ZnBiNbO5 or NTO, GZHP showed maximal photocatalytic activity (PHA) for the photocatalytic degradation of benzotriazole under visible-light irradiation. The RER of total organic carbon during the photocatalytic degradation of benzotriazole reached 90.18%, 74.35%, 70.73% or 42.15% with GZH as a photocatalyst or with Gd2YSbO7, ZnBiNbO5 or NTO as a photocatalyst after VLI-145 min. Moreover, the kinetic constant k, which came from the dynamic curve toward total organic carbon concentration and visible light irradiation time with GZH as a photocatalyst, reached 0.0110 min−1. Based on above results, GZHP showed the maximal mineralization percentage ratio when GZHP degraded benzotriazole. The results showed that hydroxyl radicals was the main oxidation radical during the degradation of benzotriazole. The photocatalytic degradation of benzotriazole with GZH as a photocatalyst conformed to the first-order reaction kinetics. Our research aimed to improve the photocatalytic properties of the single photocatalyst.