Novel Ag2O nanoparticles modified MoS2 nanoflowers for piezoelectric-assisted full solar spectrum photocatalysis.

The separation of photoinduced electrons and holes can enhance the photocatalytic properties of photocatalysts. A piezoelectric field is created inside piezoelectric materials, such as ZnO and MoS2, by applying strain. The electrons and holes become separated under the driving force of the piezoelectric field. Here, we propose combining piezoelectric MoS2 nanoflowers (NFs) and full solar response Ag2O nanoparticles (NPs) to form a MoS2@Ag2O heterostructure and achieve high efficiency full solar (UV, visible, and near-infrared) photocatalysis. Under both full solar light and ultrasonic excitation, the MoS2@Ag2O heterostructures can rapidly degrade methyl orange (MO) in aqueous solution. A built-in electric field is formed by the spontaneous polarization potential of the MoS2 NFs during this process, and an ultrasonic wave as a driving force can consecutively change the potential created by the piezoelectric effect. Under light irradiation, electrons and holes are generated in the Ag2O NPs, and the photogenerated electrons and holes with opposite signs in the two Ag2O NPs at the two surfaces of the MoS2 NFs, can be separated respectively, along the spontaneous polarized direction. Therefore, the piezoelectric effect-induced enhancement of carrier separation under ultrasonic excitation can improve the full solar photocatalytic performance of the MoS2@Ag2O heterostructures.