Au-promoted Ce-Zr catalytic filter for Pt/SnO2 sensor to selectively detect methane and ethanol in the presence of interfering indoor gases. (February 2019) - Fateminia, Fatemeh Sadat
Abstract: Ce0.8 Zr0.2 O2 mixed oxide supported gold nanoparticles (Au/Ce-Zr) as a catalytic filter was synthesized through deposition-precipitation (DP) method. SnO2 as an n-type semiconductor was prepared via the precipitation method and subsequently impregnated with H2 PtCl6 aqueous solution to produce Pt/SnO2 as the sensing material. BET surface area, XRD, FESEM, EDS and temperature programmed reduction (TPR) techniques were employed to characterize both the filter and the sensing material. CO, methane, ethanol, formaldehyde, acetone and toluene, as indoor pollutant gases, were selected to be studied with the sensor and the filter. The sensor response to CO (300 ppm), ethanol (300 ppm), and methane (500 ppm) were measured in the temperature range of 100–480 °C with and without Au/Ce-Zr catalytic filter. In the absence of the catalytic filter, Pt/SnO2 sensor detected all of the gases with comparable responses. In the presence of the filter however, the selectivity toward ethanol and methane occurred respectively at filter-sensor temperatures of 200–250 °C and 400–200 °C. Moreover, under exposure to the other interfering gases, the presence of the catalytic filter notably increased the selectivity of the sensor toward methane and ethanol at the corresponding temperatures. Based on these observations therefore, a temperature dependent sensor was fabricated through combination of the catalytic filter and the sensor.