Dynamic properties and sensitivity of semiconductor metal-oxide thick-film sensors to various gases in air gaseous medium

Study of a new evanescent wave optical fibre sensor for methane detection based on cryptophane molecules

“…The mixture was stirred at reflux temperature for 20 h. After cooling to room temperature, the solid compound was recovered by filtration to give 20 g of 1 as a beige powder (61% yield). 1 …”

“…The mixture is stirred for 15 h. After filtration the solid was washed with a methanol/water mixture (100 mL) and methanol (50 mL) to give 12.2 g of compound 4 as a white powder (93% yield). 1 H NMR (DMSO-d 6 ) δ = 6.86 (m, 6H, Ar), 5.06 (t, 2H, OH), 4.39 (d, 4H, CH 2 OH), 4.21 (s, 4H, OCH 2 ), 3.72 (s, 6H, OCH 3 ). (5).…”

“…Compound 5 was obtained as a white powder (19.8 g, 99% yield). 1 H NMR (DMSO-d 6 ) δ = 6.91 (m, 6H, Ar), 5.02 (s, 2H, OH), 4.37 (s, 4H, CH 2 OH), 4.06 (t, 4H, OCH 2 ), 3.71 (s, 6H, OCH 3 ), 2.08 (m, 2H, CH 2 ). Scheme 1.…”

“…Metal oxide thin films have been traditionally used as gas sensing materials. These sensors operate on the principle that the surface conduction of the semiconductor sensors varies in relation to the adsorption of the ambient gas [1][2][3][4]. In order to make them selective, the concept was based on the different catalytic activity of platinum and palladium towards the oxidation of methane, at around 400 • C. The detection limit attained is about 0.5% of methane [5].…”

Nanocrystalline Metal Oxides for Methane Sensors: Role of Noble Metals

“…It showed high response and high selectivity for H 2 , CH 4 , and C 4 H 10 and a little cross-sensitivity to ethanol and smoke. Malyshev and Pislyakov and his group [103] developed a production process of thick-film semiconductor gas sensors. The sensors were proved to be highly efficient for detection of methane, hexane, hydrogen, carbon monoxide, ammonia, hydrogen sulphide, and ethanol.…”