Facile synthesized highly active BiOI/Zn2GeO4 composites for the elimination of endocrine disrupter BPA under visible light irradiation

Abstract

A simple chemical bath approach for the facile synthesis of a BiOI/Zn₂GeO₄ composite has been demonstrated. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The XRD results indicate that the BiOI and Zn₂GeO₄ co-exist in the composite. The HRTEM image, showing clear lattice fringes, proves the formation of a heterojunction between BiOI and Zn₂GeO₄. The photo-degradation of bisphenol A indicates that the BiOI/Zn₂GeO₄ composites are more photoactive than BiOI and Zn₂GeO₄. The photocatalytic activity enhancement, which is mainly ascribed to the strong sensitization of BiOI to Zn₂GeO₄, broadened the photoabsorption of Zn₂GeO₄, and the heterojunction of BiOI/Zn₂GeO₄ facilitated the transfer and separation of photo-generated charge carriers. In addition, the active species trapping experiments showed that h⁺ and ˙O₂⁻ were the dominant reactive species, while molecular oxygen plays a fatal role for photocatalytic interactions. Subsequently, a possible degradation mechanism is proposed. Furthermore, the BiOI/Zn₂GeO₄ photocatalysts exhibit a higher mineralization capacity for bisphenol A, suggesting hopeful prospects for its use in practical applications for the decomposition of organic pollutants.