Salt-assisted Synthesis of Hollow Bi 2 WO 6 Microspheres with Superior Photocatalytic Activity for NO Removal

摘要

Hollow Bi(2)W0(6) microspheres are successfully synthesized by a facile ultrasonic spray pyrolysis (USP) method using NaCl as a salt template. The as-prepared hollow microspheres assembled as nanoplates with dimensions of approximately 41-148 nm and are dispersed with non-uniform pores on the template surface. By swapping the salt template with KC1 or Na2SO4, different morphologies of Bi(2)W0(6) are obtained. The experimental results demonstrate that NaCI plays a key role on the formation of Bi(2)W0(6) with hollow structures. The specific growth mechanism of hollow microspheres was studied in detail. The Bi(2)W0(6) hollow microspheres exhibit an excellent photocatalytic efficiency for NO removal under solar light irradiation, which is 1.73 times higher than for the Bi(2)W0(6) obtained in the absence of any salt template. This enhancement can be ascribed to the simultaneous improvement on the surface area and visible light -harvesting ability from the hollow structures. Electron spin resonance (ESR) results suggest that both radicals of "OH and O-2-are involved in the photocatalytic process over the BWO-NaC1 sample. The production of O-2 radicals offers better durability for NO removal.