Selective detection of methane and butane by temperature modulation in iron doped tin oxide sensors

In the present study we find that it is possible to develop sensors based on iron doped tin dioxide, which can detect both methane and butane (present in CNG and LPG, respectively) at a temperature of 350 degrees C. However, the same sensors can selectively detect butane at a temperature of 425 degrees C. Such differential behaviour can be explained by considering the decrease in the number and/or strength of Lewis acid sites on SnO2 due to Fe-doping and the role of chain length on the adsorption-desorption characteristics of alkanes. However, the incorporation of palladium as a catalyst in Fe-doped SnO2 sensors removes the typical selectivity, and the temperatures of the maximum response coincide for methane and butane. (c) 2005 Elsevier B.V. All rights reserved.