Solvothermal synthesis of bismuth molybdate hollow microspheres with high photocatalytic activity.

Bi2MoO6 hollow microspheres were successfully synthesized by a simple solvothermal process without using any hard template or surfactant. The effect of solvent and urea on the morphology of the samples was studied systematically. The results indicate that the composition of the mix ethylene glycol/absolute ethanol solvents and the urea content play a key role in the final formation of hollow microspheres. Based on the experimental results, the formation mechanism of the hollow interior by an EG-induced Ostwald ripening process was proposed for the Bi2MoO6 hollow microspheres. The Bi2MoO6 hollow microspheres exhibit higher catalytic activity than the Bi2MoO6 particles for degradation of Rhodamine B under visible-light irradiation (lambda > 420 nm). Further investigation revealed that the surface area, grain size, and hollow structure of the as-prepared Bi2MoO6 microspheres are responsible for the improvement of the photocatalytic activity.