Facile Hydrothermal Synthesis and Enhanced Methane Sensing Properties of Pt-Decorated ZnO Nanosheets.

Pure and Pt-decorated ZnO nanosheets were synthesized via a facile and environment-friendly hydrothermal process, and characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS), respectively. Side-heated chemical gas sensors were fabricated with the synthesized ZnO based powders and their sensing properties to methane CH4, an important characteristic hydrocarbon contaminant extracted from power transformer oil with overheating or discharging fault, were systemically investigated. Interestingly, Pt decoration not only obviously increased the gas response of sensor fabricated with the synthesized ZnO nanosheets to CH4, but also effectively reduced its optimum operating temperature. Its highest response to 50 ppm of CH4 was about 63.45 at 240 °C, which was about two times larger when compared with the pure one. Meanwhile, the Pt-decorated ZnO nanosheets sensor exhibited shorter response-recovery characteristic, good linearity in low concentration range and excellent stability towards CH4. Those superior sensing features indicate the synthesized Pt-decorated ZnO nanosheets is a promising candidate for fabricating high-performance CH4 sensor.

Fabrication and Characterization of Highly Sensitive Acetone Chemical Sensor Based on ZnO Nanoballs.

Highly sensitive acetone chemical sensor was fabricated using ZnO nanoballs modified silver electrode. A low temperature, facile, template-free hydrothermal technique was adopted to synthesize the ZnO nanoballs with an average diameter of 80 ± 10 nm. The XRD and UV-Vis. studies confirmed the excellent crystallinity and optical properties of the synthesized ZnO nanoballs. The electrochemical sensing performance of the ZnO nanoballs modified AgE towards the detection of acetone was executed by simple current-voltage (I-V) characteristics. The sensitivity value of ∼472.33 µA·mM-1·cm-2 and linear dynamic range (LDR) of 0.5 mM-3.0 mM with a correlation coefficient (R²) of 0.97064 were obtained from the calibration graph. Experimental limit of detection (LOD) for ZnO nanoballs modified AgE was found to be 0.5 mM.

Synthesis, Characterization and Enhanced Sensing Properties of a NiO/ZnO p-n Junctions Sensor for the SF6 Decomposition Byproducts SO2, SO2F2, and SOF2.

The detection of partial discharge and analysis of the composition and content of sulfur hexafluoride SF6 gas components are important to evaluate the operating state and insulation level of gas-insulated switchgear (GIS) equipment. This paper reported a novel sensing material made of pure ZnO and NiO-decorated ZnO nanoflowers which were synthesized by a facile and environment friendly hydrothermal process for the detection of SF6 decomposition byproducts. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structural and morphological properties of the prepared gas-sensitive materials. Planar-type chemical gas sensors were fabricated and their gas sensing performances toward the SF6 decomposition byproducts SO2, SO2F2, and SOF2 were systemically investigated. Interestingly, the sensing behaviors of the fabricated ZnO nanoflowers-based sensor to SO2, SO2F2, and SOF2 gases can be obviously enhanced in terms of lower optimal operating temperature, higher gas response and shorter response-recovery time by introducing NiO. Finally, a possible gas sensing mechanism for the formation of the p-n junctions between NiO and ZnO is proposed to explain the enhanced gas response. All results demonstrate a promising approach to fabricate high-performance gas sensors to detect SF6 decomposition byproducts.