Synthesis of BiOCl/TiO 2 –zeolite composite with enhanced visible light photoactivity

Abstract

Abstract The BiOCl/TiO2–zeolite composite was synthesized via a hydrolysis–precipitation method. The prepared samples were characterized by X-ray diffraction, thermogravimetric analysis, N2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV–vis diffused reflectance spectroscopy and photoluminescence. Using liquid rhodamine B and gaseous formaldehyde as the target pollutants, the visible light photoactivity of as received BiOCl/TiO2–zeolite composites was evaluated. Compared with bare BiOCl and TiO2, the composites exhibited considerably enhanced photoactivity for rhodamine B and gaseous formaldehyde. The enhancement should be attributed to the higher adsorption ability and the formation of effective BiOCl/TiO2 heterojunction in BiOCl/TiO2–zeolite composite. The influence of calcination temperatures on the photocatalytic performance of BiOCl/TiO2–zeolite composite was also investigated. The optimal calcination temperature is identified as 400 °C for liquid RhB decoloration due to the highest RhB adsorption capacity of composite. However, the composite calcined at 600 °C displayed the best gaseous formaldehyde degradation because of the high crystallinity of TiO2 and abundant (001) facets of BiOCl. This result further indicated that the enhanced photoactivity of BiOCl/TiO2–zeolite composite should be attributed to the coexistence of higher surface area and proper crystallinity. The BiOCl/TiO2–zeolite composite has broad application foreground in pollutants purification.