Nanocrystalline SnO(2) Functionalized with Ag(I) Organometallic Complexes as Materials for Low Temperature H(2)S Detection

This paper presents a comparative analysis of H(2)S sensor properties of nanocrystalline SnO(2) modified with Ag nanoparticles (AgNPs) as reference sample or Ag organic complexes (AgL1 and AgL2). New hybrid materials based on SnO(2) 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 H(2)S demonstrated high sensitivity, selectivity toward other reducing gases (H(2) (20 ppm), NH(3) (20 ppm) and CO (20 ppm)) and good reproducibility of the composites in H(2)S detection at low operating temperatures. The composite materials also showed a linear detection range in the concentration range of 0.12–2.00 ppm H(2)S even at room temperature. It was concluded that the predominant factors influencing the sensor properties and selectivity toward H(2)S in low temperature region are the structure of the modifier and the chemical state of silver. Thus, in the case of SnO(2)/AgNPs reference sample the chemical sensitization mechanism is more possible, while for SnO(2)/AgL1 and SnO(2)/AgL2 composites the electronic sensitization mechanism contributes more in gas sensor properties. The obtained results show that composites based on nanocrystalline SnO(2) and Ag(I) organic complexes can enhance the selective detection of H(2)S.