Enhanced photocatalytic properties of defect-rich α-MoO3 nanoflakes by cavitation and pitting effect

Abstract For the first time, we present a novel, facile and eco-friendly engineering defect method, to produce defect-rich α-MoO 3 ( dr- MoO 3 ) nanoflakes with abundant exposed reactive edge sites, by applying cavitation and pitting effect of high-power ultrasonic tip to inch-size α-MoO 3 single crystals. The as-prepared dr- MoO 3 nanoflakes deliver excellent photocatalytic activity for degradation of Rhodamine B (RhB) under visible light irradiation. The degradation apparent rate constant k of dr- MoO 3 is as large as 5.9 × 10 −2  min −1 , which is ˜6.6 times higher than commercial α-MoO 3 ( com- MoO 3 ). The superior photocatalytic performance of dr- MoO 3 is attributed to its rich exposed edges and slight expansion of interlayer space, which not only enhance the adsorption of H 2 O and OH − , provide abundant highly reactive sites, but also shorten the distance of photogenerated carriers moving to the reactive sites. This work provides new insights into the self-enhancement of α-MoO 3 photocatalytic activities, which could be extended to other layered semiconductor photocatalysts.