Controlled synthesis of olive-shaped Bi2S3/BiVO4 microspheres through a limited chemical conversion route and enhanced visible-light-responding photocatalytic activity

Well-defined olive-shaped Bi2S3/BiVO4 microspheres were synthesized through a limited chemical conversion route (LCCR), where olive-shaped BiVO4 microspheres and thioacetamide (TAA) were used as precursors and sulfur source, respectively. The as-synthesized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission microscope (HRTEM), X-ray photoelectron spectra (XPS), UV-visible diffuse-reflectance spectroscopy (UV-vis DRS), and photoluminescence (PL) spectra in detail. Compared with pure BiVO4 microspheres and Bi2S3 nanorods, the Bi2S3/BiVO4 products showed obviously enhanced photocatalytic activity for the degradation of rhodamine B (Rh B) in aqueous solution under visible-light irradiation (lambda > 400 nm). In addition, the Bi2S3/BiVO4 composite microspheres showed good visible-light-driven photocatalytic activity for the degradation of refractory oxytetracycline (OTC) as well. On the basis of UV-vis DRS, the calculated energy band positions, and PL spectra, the mechanism of enhanced photocatalytic activity of Bi2S3/BiVO4 was proposed. The present study provides a new strategy to design composite materials with enhanced photocatalytic performance.