Synthesis and characterization of catalytic metal semiconductor-doped siliceous materials with ordered structure for chemical sensoring

Sensing materials based on doped mesoporous silica of SBA-15 type were obtained by repeated wet impregnation of the solid with semiconductive oxides (Sn and In) and noble metal (Pt). The mesoporous structure of SBA was preserved during the doping and calcination of the solid, although slight pore size narrowing occurred as shown by the BET adsorption analysis. The solid was deposited by the casting technique as a thin layer on a finger structure. The modifications of its electrical resistance values in the presence of hydrogen and propene (50-400 ppm), at temperature values of 450°C was used as sensing parameter, in the presence of propene and hydrogen. The sensitivity to propene was higher than that to hydrogen.