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Novel Ag2O nanoparticles modified MoS2 nanoflowers for piezoelectric-assisted full solar spectrum photocatalysis
摘要： 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.
关键词： Piezoelectric,MoS2 nanoflowers,Full solar light,Photocatalytic,Ag2O nanoparticles
更新于2025-09-23 15:21:21
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Controlled synthesis of ultrathin MoS <sub/>2</sub> nanoflowers for highly enhanced NO <sub/>2</sub> sensing at room temperature
摘要： Fabrication of a high-performance room-temperature (RT) gas sensor is important for the future integration of sensors into smart, portable and Internet-of-Things (IoT)-based devices. Herein, we developed a NO2 gas sensor based on ultrathin MoS2 nanoflowers with high sensitivity at RT. The MoS2 flower-like nanostructures were synthesised via a simple hydrothermal method with different growth times of 24, 36, 48, and 60 h. The synthesised MoS2 nanoflowers were subsequently characterised by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The petal-like nanosheets in pure MoS2 agglomerated to form a flower-like structure with Raman vibrational modes at 378 and 403 cm?1 and crystallisation in the hexagonal phase. The specific surface areas of the MoS2 grown at different times were measured by using the Brunauer–Emmett–Teller method. The largest specific surface area of 56.57 m2 g?1 was obtained for the MoS2 nanoflowers grown for 48 h. This sample also possessed the smallest activation energy of 0.08 eV. The gas-sensing characteristics of sensors based on the synthesised MoS2 nanostructures were investigated using oxidising and reducing gases, such as NO2, SO2, H2, CH4, CO and NH3, at different concentrations and at working temperatures ranging from RT to 150 °C. The sensor based on the MoS2 nanoflowers grown for 48 h showed a high gas response of 67.4% and high selectivity to 10 ppm NO2 at RT. This finding can be ascribed to the synergistic effects of largest specific surface area, smallest crystallite size and lowest activation energy of the MoS2-48 h sample among the samples. The sensors also exhibited a relative humidity-independent sensing characteristic at RT and a low detection limit of 84 ppb, thereby allowing their practical application to portable IoT-based devices.
关键词： gas sensing,room temperature,hydrothermal synthesis,MoS2 nanoflowers,NO2 gas sensor
更新于2025-09-23 15:19:57