Solvothermal Synthesis of Bi2WO6 Hollow Microspheres Via Ostwald Ripening with Their Enhanced Photocatalytic Activity

Bi2WO6 hollow microspheres were successfully synthesized by solvothermal process in the presence of urea at proper ethylene glycol (EG)/absolute ethanol (AE) volume ratio (1:1). The samples consisted of microspheres with an average diameter of 1 mu m, and the shell consisted of numerous nanoplates. The effect of solvent, the ratio of EG/AE solvents and urea amount on the morphology of the samples was studied systematically, indicating that a certain ratio of EG/AE and urea amount played an important role in the formation of hollow microspheres. Based on the detailed investigation, the formation mechanism of the hollow interior by EG-induced Ostwald ripening process was proposed. By contrast, the Bi2WO6 hollow microspheres exhibited higher catalytic activity for degradation of Rhodamine B under xenon lamp irradiation, and nearly 100 % Rhodamine B is degraded within 120 min.