Pure SnO₂Gas Sensor with High Sensitivity and Selectivity towards C₂H₅OH

To observation, poisonous gases in the environment, Sensors with high selectivity, high response and low operating temperature are required. In this work, pure SnO2 nanoparticles was prepared by using a simple and inexpensive technique (hydrothermal method) without a template. Various confirmatory tests were performed to characterize SnO2 nanoparticles such as energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transition Electron Microscopy (TEM), during the detection of the gas, we found that pure SnO2 nanoparticles has a high selectivity for ethanol to 100 ppm at a low temperature (180°C) and a high response (about 27 s) and a low detection limit of 5 ppm, also it have response/recovery times about (4 s, 2 s) respectively. The distinctive sensing properties of SnO2 sensor make it a promising candidate for ethanol detection. Furthermore, the gas-sensing mechanism have been examined.

Silicon quantum dots-based fluorescent sensor for the detection of cobalt with high sensitivity and selectivity

Fluorescent silicon quantum dots(Si QDs)were hydrothermally synthesized from a mixture of 3(2-aminoethylamino)propyl(dimethoxymethylsilane)(AEAPDMMS)and poly(vinylpyrrolidine)(PVP).The resulting Si QDs exhibited good water solubility and high stability.Under the optimized conditions,the probe revealed an excellent linear fluorescence quenching effect on Co2+ranging from 1μmol/L to 120μmol/L with a limit of detection of 0.37μmol/L(based on 3 s/k).The quenching mechanism was studied,showing that static quenching(SQE)causes the main effect.Furthermore,the test paper based on Si QDs was prepared,which is cost-effective,high sensitivity,good selectivity,easy to use and show excellent anti-interference capability.This method was applied to analyze the content of Co2+in environmental water samples with satisfying results.