Thermoelectric CO Gas Sensor Using Thin-Film Catalyst of Au and Co[sub 3]O[sub 4]

Thin-film catalysts of gold and cobalt oxide were prepared by magnetron radio frequency sputtering deposition on magnesia substrate by cosputtering Au and We investigated the catalytic activity of this thin-film catalyst for CO gas and found that the catalytic activity was influenced strongly by the contents of the supported oxides in the thin film. Using this catalyst, a thermoelectric gas sensor of [Au, was developed to detect carbon monoxide gas. When this sensor is exposed to the gas mixture of air and CO, the catalytic reaction oxidation of CO heats up the catalyst-coated surface and then thermoelectric voltage builds up along the hot and cold region of the thermoelectric film of SiGe. The sensor of [Au, showed a temperature increase of about 6.6°C in the hot region and an output voltage signal of about 0.63 mV for 3% CO in air at 200°C. The sensor showed a clear voltage signal with good linearity for the target gas content in the range 0.05-3.0% and high selectivity for CO gas at 200°C.