Hydrogen sulfide sensor based on tin oxide deposited by spray pyrolysis and microwave plasma chemical vapor deposition

Abstract

Spray pyrolysis and microwave plasma chemical vapor deposition techniques have been employed successfully for the deposition of CuO impregnated SnO2 films suitable for sensing hydrogen sulfide and methyl mercaptan. The observed change in conductivity of these films upon exposure to H2S gas in air has been explained on the basis of the band theory of solids.

Ultrasensitive and ultraselective detection of H2S using electrospun CuO-loaded In2O3 nanofiber sensors assisted by pulse heating

“…In case of In 2 O 3 nanofibers, the gas response toward 5 ppm H 2 S monotonously decreases with increasing sensor temperature and the sensor shows a response of 6.9 × 10 3 and 515 at 25 and 150 • C, respectively. In contrast, the response of a sensor made of CuO-loaded In 2 O 3 composite nanofibers toward 5 ppm H 2 S is as high as 1.16 × 10 5 at 150 • C. Table 1 summarizes the H 2 S responses and operating temperatures of CuO-loaded n-type oxide semiconductors in the literature and of the CuO-loaded In 2 O 3 nanofibers of the present study [32][33][34][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. To the best knowledge of the authors, the response of 1.16 × 10 5 toward 5 ppm H 2 S is one of highest values ever reported.…”

Heterocontact type CuO-modified SnO2 sensor for the detection of a ppm level H2S gas at room temperature

“…Known H 2 S gas (20-1200 ppm) sensors [4][5][6][7][8][9][10][11][12][13][14] showed relatively lower response (∼10 3 ) at higher temperatures (150-250 • C). However, it is inadequate to operate the sensors at higher temperatures.…”

“…Materials like ZnO, SnO 2 , Fe 2 O 3 , Ga 2 O 3 , etc. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] have been known to detect inflammable and toxic gases. The gas sensing characteristics of the materials can be improved by incorporating some additives [20][21][22] into the oxide films.…”

Contribution of adsorbed oxygen and interfacial space charge for enhanced response of SnO2 sensors having CuO catalyst for H2S gas

“…The sensor conductance (G gc ) of SCO-CONT structure in the presence of H 2 S gas is mainly governed by the conversion of CuO to CuS, which is reported to be more metallic than CuO [30]. Therefore, the CuO after conversion (into CuS) becomes a less p-type semiconducting material and allows the penetration of depletion region at the interface (CuO-SnO 2 ) to extend more towards the catalyst over-layer and less into the n-type SnO 2 thin film.…”