Analysis of SnO2|WO3 Heterocontact Properties during the Detection of Hydrogen Sulphide

Abstract

The main objective of the paper was the analysis of the properties of SnO2|WO3 heterocontact as well as the determination of its response to 50 ppm of hydrogen sulphide. It was noticed that the sensitivity of the sensor being tested to hydrogen sulphide depended significantly on the polarization direction. When its parameters were compared with those of sensors the gas-sensitive layer of which was made only from one type of metal oxide, a high impact of the heterocontact on the electric charge transport was noticed. The value of the activation energy of the electric conductivity is clearly dependent on the polarization direction. A mechanism of physicochemical processes occurring in a planar sensor with a heterocontact was suggested, and three areas differing in the width of depleted layer, where the inter-phase boundary of SnO2|WO3 had the most essential impact on the parameters of the sensor being tested, were distinguished and described.

Hybrid SnO2/TiO2 Nanocomposites for Selective Detection of Ultra-Low Hydrogen Sulfide Concentrations in Complex Backgrounds

“…In the steady state condition, the formation of an electron-enriched zone at the tin dioxide side of the interface enhances oxygen adsorption in this region [18,41]. Additionally, it leads to a more substantial depletion of titanium dioxide grains and formation of contact potential at the SnO 2 /TiO 2 boundary.…”

“…It was reported that grain boundaries between different oxides have higher catalytic activity, compared to single-oxide grain boundaries [13,14,15,16,17]. Recently, SnO 2 -based metal oxide structures with n-p and n-n heterojunction have attracted a great deal of interest as gas sensing materials [2,13,14,15,16,17,18,19]. …”

“…Enhanced detection of H 2 S has been reported by using different heterojunction structures SnO 2 /CuO, SnO 2 /WO 3 and SnO 2 /ZnO [3,4,18,21]. The sensitivity of multilayer oxides was found to be close to the sensitivity of novel nanomaterials, but at the same time the thin film sensors demonstrated high stability and repeatability.…”

The Impact of Sepiolite on Sensor Parameters during the Detection of Low Concentrations of Alcohols

“…Electric measurements were carried out at a test stand comprising a HP E3632 A power supply unit type (Agilent Technologies Inc., Santa Clara, CA, USA), a Keithley 2400 current–voltage source, the measurement chamber and a PC provided with appropriate software. Current-voltage characteristics of sensors at various temperatures were recorded using an potentiostat-galvanostat type SI 1287 from Solartron Analytical (Farnborough, UK), with the use of the CorrWare software from Scribner Associates Inc. (Southern Pines, NC, USA) [15]. …”

Gas-sensing properties and in-situ diffuse-reflectance Fourier-transform infrared spectroscopy study of diethyl ether adsorption and reactions on SnO2 film

“…1). The reactions of adsorption of O 2 and diethyl ether during this process may be described as follows [36]:…”