Abstract
This paper presents a comparative analysis of H2S sensor properties of nanocrystalline SnO2 modified with Ag nanoparticles (AgNPs) as reference sample or Ag organic complexes (AgL1 and AgL2). New hybrid materials based on SnO2 and Ag(I) organometallic complexes were obtained. The microstructure, compositional characteristics and thermal stability of the composites were thoroughly studied by X-ray diffraction (XRD), X-ray fluorescent spectroscopy (XRF), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TGA). Gas sensor properties to 2 ppm H2S demonstrated high sensitivity, selectivity toward other reducing gases (H2 (20 ppm), NH3 (20 ppm) and CO (20 ppm)) and good reproducibility of the composites in H2S detection at low operating temperatures. The composite materials also showed a linear detection range in the concentration range of 0.12–2.00 ppm H2S even at room temperature. It was concluded that the predominant factors influencing the sensor properties and selectivity toward H2S in low temperature region are the structure of the modifier and the chemical state of silver. Thus, in the case of SnO2/AgNPs reference sample the chemical sensitization mechanism is more possible, while for SnO2/AgL1 and SnO2/AgL2 composites the electronic sensitization mechanism contributes more in gas sensor properties. The obtained results show that composites based on nanocrystalline SnO2 and Ag(I) organic complexes can enhance the selective detection of H2S.
Highlights
IntroductionHydrogen sulfide (H2 S) is a colorless gas with an unpleasant smell of rotten eggs, causes severe corrosion of metals and is explosive in a mixture with air in the range of 4–45%
Hydrogen sulfide (H2 S) is a colorless gas with an unpleasant smell of rotten eggs, causes severe corrosion of metals and is explosive in a mixture with air in the range of 4–45%vol The main H2 S sources are petroleum refining process, natural gas, geothermal sources, bacterial breakdown of organic matter and industrial activities [1]
Of 1 ppm and a 15 min short-term exposure limit (STEL) of 5 ppm was recommended by the American Conference of Governmental Industrial Hygienists (ACGIH)
Summary
Hydrogen sulfide (H2 S) is a colorless gas with an unpleasant smell of rotten eggs, causes severe corrosion of metals and is explosive in a mixture with air in the range of 4–45%. Vol The main H2 S sources are petroleum refining process, natural gas, geothermal sources, bacterial breakdown of organic matter and industrial activities [1]. Hydrogen sulfide is a toxic gas, affecting directly the human nervous and respiratory systems. According to the recommendation of National Institute for Occupational Safety and Health (NIOSH) of the USA the acceptable 10-min ceiling limit for. Of 1 ppm and a 15 min short-term exposure limit (STEL) of 5 ppm was recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).
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