Facile solvothermal synthesis of hierarchical flower-like Bi 2 MoO 6 hollow spheres as high performance visible-light driven photocatalysts

A facile template-free method has been developed for the controllable fabrication of novel hierarchical flower-like Bi2MoO6 hollow spheres via a solvothermal process in the presence of ethylene glycol. The formation mechanism was proposed based on the evolution of morphology as a function of solvothermal time, which involves the initial formation of nanoparticles followed by their self-aggregation to microspheres and transformation into hierarchical flower-like hollow spheres by Ostwald ripening. The integer appearance of the hierarchical flower-like Bi2MoO6 hollow spheres was maintained after calcination at 400 °C for 3 h. Furthermore, the calcined hierarchical flower-like Bi2MoO6 hollow spheres exhibited excellent visible-light-driven photocatalytic efficiency for the degradation of Rhodamine B, up to 95% within 2 h, which was much higher than that of Bi2MoO6 prepared by solid-state reaction and TiO2 (P25). The improved photocatalytic performance could be ascribed to the special hierarchical hollow sphere structure, good permeability and large surface area.