Construction of TiO2@Bi2WO6 hollow microspheres by template method for enhanced degradation of ethylene under visible light

Abstract

Abstract A series of TiO2@Bi2WO6 hollow microspheres were constructed by using the solvothermal method with carbon microspheres as a template. The morphology and structure of the TiO2@Bi2WO6 hollow microspheres were characterized, and their activities were evaluated for the photocatalytic degradation of ethylene under visible-light irradiation. The results show that the solvothermal reaction conditions applied for the synthesis of the hollow microspheres played a role on their photocatalytic activity. When 20 wt% Bi2WO6 was added in the mixture and synthesis reaction temperature and time were 90 °C and 3 h, respectively, the TiO2@Bi2WO6hollow microspheres exhibited the highest photocatalytic activity with degradation of ethylene reaching 16.82%, which increased by 387% and 95% compared with those of TiO2 hollow microspheres and Bi2WO6 powder, respectively. The improvement in photocatalytic efficiency is attributed mainly to the high-specific-surface-area hollow structure which contains a large number of tiny pores on the microsphere surface and increases the contact probability between ethylene molecule and photocatalyst. The increase in the number of oxygen vacancies and surface defects improves the separation efficiency of photogenerated electron-hole pairs. In addition, TiO2 and Bi2WO6 create a heterojunction, which narrows the band gap of TiO2@Bi2WO6 and enhances the absorption of visible light.