Low temperature Pd/SnO2 sensor for carbon monoxide detection

The development of a tin oxide nanoparticle based sensor for detecting carbon monoxide at low temperature, 60 °C is presented. A combination of three approaches namely, (1) addition of a catalytic metal – 1.5% palladium, (2) optimization of organic binder content, and (3) a proper design of electrodes, leads to high sensitivity, excellent repeatability, and long-term stability in sensor response. The sensors have been tested in dry (<1% RH) and humid (>70% RH) conditions, and no humidity effect on the sensor performance was noticed. The sensors using 15% hydroxypropyl cellulose (HPC) mixed with Pd/SnO2 show sensitivity to CO gas in the parts per million (ppm) level of concentration, 5–10% repeatability in 6–18 ppm CO exposures, and active response for more than 40 days. In addition, the fatigued sensors were recoverable with a brief heating process.