Thermoelectric gas sensor with CO combustion catalyst for ppm level carbon monoxide detection

Thermoelectric gas sensors (TGS) for microcalorimeters with a CO combustion catalyst were fabricated and tested for the detection of ppm level CO. Two types of CO combustion catalysts containing 3 wt% Au, Pd, and Pt loaded on CoO and Co₃O₄ were prepared through a colloidal mixing process and integrated on the TGS. The 3 wt% AuPdPt loaded on the CoO and Co ₃O₄ catalysts exhibited stable CO combustion performance at temperatures as low as 200 C, which is a much lower temperature than that of a previous study using a Au/Co₃O₄ catalyst. The TGS of 3 wt%(AuPdPt)/CoO catalyst showed better CO selectivity than that of Co ₃O₄, and could detect CO over a wide concentration range from 1 ppm to 1% (v/v) CO in air, with a gas concentration resolution of 1 ppm CO, signal to noise ratio of 6.8, and CO selectivity against H₂ of 1.75.