Tin oxide gas sensor on tin oxide microheater for high-temperature methane sensing

Despite the ever-increasing demand for methane detectors in residential and industrial locations, a long life semiconductor-based methane sensor is yet elusive. The problem is rooted in the high decomposition temperature of the methane molecule. Here, we disclose a tin oxide gas sensor heated up to its operating temperature using a ten micron-thick undoped tin oxide microheater which can operate at temperatures as high as 850 degrees C, sufficient for the spontaneous pyrolysis of methane. Operating at temperatures above 700 degrees C, the device selectively senses methane in atmospheres contaminated with CO and H-2. The response and recovery times are both similar to 10 s, and the CH4 detection limit is 50 ppm, rendering the developed sensor appropriate for online measurement of methane level in hot exhaust gases. Operating continuously at 700 degrees C in air, the device exhibits no noticeable aging in a test duration of 30 days. (C) 2019 Published by Elsevier B.V.