Dual selective Pt/SnO2 sensor to CO and propane in exhaust gases of gasoline engines using Pt/LaFeO3 filter

In this study, a novel dual selective Pt/SnO2 sensor to carbon monoxide and propane in exhaust gases of a gasoline engine, using a Pt/LaFeO3 perovskite catalytic filter, is presented. SnO2 was prepared by a sol-gel method and LaFeO3 by a combustion synthesis method. The samples were impregnated with aqueous solutions of H2PtCl6 to get 1.0 wt% Pt/SnO2 and 1.0 wt% Pt/LaFeO3. BET surface area measurement, XRD, EDS, TEM, HR-TEM, temperature programmed methods of reduction (TPR) and O-2-desorption (TPD) analyses were carried out to investigate surface and bulk properties of the samples. In a mixture of 10,000 ppm carbon monoxide, 1000 ppm nitric oxide and 1000 ppm propane in 1.0% oxygen, Pt/LaFe03 catalytic filter-Pt/SnO2 sensor combination is selective to CO and C3H8 at the temperature ranges of 150-250 and 350-400 degrees C, respectively. In the temperature range of 150-250 degrees C, the filter-sensor combination has a significant response to CO, whereas negligible response to C3H8 and NO is observed. On the other hand, at temperatures higher than 350 degrees C, CO and NO in the mixture are completely converted to almost inert products on the filter and the sensor shows a response only to C3H8. (C) 2014 Elsevier B.V. All rights reserved.