Abstract
Thin films of tin oxide mixed cerium oxide were grown on unheated substrates by physical vapor deposition. The films were annealed in air at 500 °C for two hours, and were characterized using X-ray photoelectron spectroscopy, atomic force microscopy and optical spectrophotometry. X-ray photoelectron spectroscopy and atomic force microscopy results reveal that the films were highly porous and porosity of our films was found to be in the range of 11.6–21.7%. The films were investigated for the detection of carbon monoxide, and were found to be highly sensitive. We found that 430 °C was the optimum operating temperature for sensing CO gas at concentrations as low as 5 ppm. Our sensors exhibited fast response and recovery times of 26 s and 30 s, respectively.
Highlights
There is an ever-increasing demand for gas sensors in various fields
CeO2 has a relatively complex Ce 3d XPS spectrum that consists of six peaks, which correspond to the three pairs of spin-orbit doublets of oxidized CeO2 [13]
The first three peaks correspond to Ce 3d5/2 and the last two peaks correspond to Ce 3d3/2
Summary
There is an ever-increasing demand for gas sensors in various fields. Particular attention has been devoted to the monitoring of carbon monoxide (CO). More precise control of the air/fuel ratio in a combustion processes can yield significant gains in efficiency and result in substantial savings in fuel consumption. The flue gas concentration of CO is a reliable and accurate indication of the completeness of combustion, as it is the most sensitive indicator of unburned combustible losses. Metal oxide semiconductors have been employed in the detection of CO. One of the advantages of Sensors 2012, 12 these materials is that they enable high temperature operation, making them unique for hostile industrial applications. Many gas reactions are plausible only at such elevated temperatures
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