GS2.2 - A Low Temperature Formaldehyde Gas Sensor Based on Hierarchical SnO/SnO2 Nano-flowers Assembled from Ultrathin 2D Nano-sheets

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
Gas Sensors 2
N. Li, Z. Cheng, X. Wang, Q. Xiang, J. Xu - NEST Lab,Department of Chemistry, College of Science, Shanghai University (China)
97 - 98


In the field of gas sensors, semiconductor metal oxide with high temperature, high energy consumption is an important issue that we need to pay attention to. In this paper, we have successfully synthesized low-temperature formaldehyde gas sensors using hetero-junction generation. Hierarchical SnO/SnO2 Nano-flowers assembled from ultrathin Nano-sheets were obtained via facile and one-step hydrothermal approach by adjusting the solvent ratio. XRD, FESEM, and FETEM analysis were carried out to investigate the element composition and morphology of hierarchical SnO/SnO2. The diameter of hierarchical SnO/SnO2 Nano-flowers is approximately 400-500 nm and the thickness of ultrathin 2D Nano-sheets is about 20nm. Compared with pure hierarchical SnO2 Nano-flowers, the SnO/SnO2 gas sensor shows excellent selectivity, good stability, and high response for formaldehyde detection at the best working temperature of 120°C. The response value can be 8.5 when the concentration of formaldehyde down to 1ppm, moreover, the sensor showed low detection limit (4.96ppb) to formaldehyde. This excellent gas sensing properties of SnO/SnO2 Nano-flowers can be attributed to hetero-junction of SnO/SnO2 and unique hierarchical structure assembled from ultrathin 2D Nano-sheets, which can provide more active sites when in contact with formaldehyde. Finally, sensing mechanism can be proved by BET, XPS, and mass spectrometry in detail.