Thermally modulated multi sensor arrays of SnO2/additive/electrode combinations for enhanced gas identification

We report the development of a multi sensor array integrated with four different layers of tin oxide/additive combinations, which operates thermo-cyclically by triangular heater voltages, for specific gas identification. These multi sensor arrays could yield simultaneously four different patterns of dynamic conductance, which can be used for specific gas component analysis. Pure SnO2, SnO2/Sb2O3, SnO2/Sb2O3/La2O3 and SnO2/Sb2O3/CuO were used as sensing materials on a single chip with Au or Pt as electrode material to study the response behavior to propene, CO and methane at different concentrations and temperature rates/cycle time. The nature of the specific gas recognition patterns is highly determined by additive material, electrode metallization, temperature rate, type of gas and gas concentration. The specific gas behavior is discussed in connection with the reaction processes taking place at the pores of the sensing layer and at the triple phase boundary of layer, electrode and gas.