High-performance temperature-selective SnO2:Cu-based sensor

• Published in: Materials letters Vol. 57; no. 15; pp. 2177 - 2184
• Main Authors: More, P.S., Khollam, Y.B., Deshpande, S.B., Sainkar, S.R., Date, S.K., Karekar, R.N., Aiyer, R.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2003; Elsevier
• Subjects: Analysis methods; Applied sciences; Atmospheric pollution; Exact sciences and technology; Gas sensor; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Microstructure; Oxides; Physics; Pollution; Selectivity; Sensitivity; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; SnO2/Cu system; SnO2/Cu system; Oxides; Sensitivity; Gas sensor; Selectivity; Microstructure; Performance evaluation; Methane; Chemical sensors; Inorganic compounds; Sensitivity analysis; Impurity density; Doped materials; Copper additions; Sensor materials; Tin oxides; Impurity effect; Temperature effects; Air pollution; Carbon monoxide; Hydrogen molecules; Gas detector
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(02)01170-9

Systematic evaluation of gas-sensing characteristics of Cu-modified SnO2 pellets for CO, H2 and CH4 gases from ppm to percentage level is reported. The concentration level of Cu additive was varied systematically from 1 to 11 wt %. The highest values of sensitivity factor (SF) of 240 and 590 corresponding to CO and H2 gases were obtained at considerably lower temperatures of 160 and 230 °C, respectively, for 9 wt.% of Cu. The selectivity values are found to be maximum at 7 and 9 wt.% of Cu for H2 (≈78) and CO (≈1.9) gasses, respectively. For CH4 gas, on the contrary, the sensor showed quite inferior response. The sensitivity curve for our material follows the usual trend of three-region behaviour of standard Windischmann and Mark's curve. The sensor tends to saturate at 1.5% and 3.6% for CO and H2, respectively. XRD and scanning electron micrograph (SEM) characterisation techniques are used to pinpoint the possible reasons for high performance of the sensor at 9 wt.% Cu. Our sensor material showed promising properties for gas-sensing (CO and H2) applications.