Influence of the reactant gas on the electrical properties of alumina-supported tin dioxide catalysts

The surface dynamics of SnO 2 /γ-Al 2 O 3 catalysts with different tin dioxide loadings (3 and 20 wt%) prepared by the impregnation method were investigated by using in situ electrical/dielectric measurements. The samples were characterized by BET, inductively coupled plasma atomic emission spectroscopy and X-ray diffraction methods. The propylene oxidation reaction, in the temperature range of 30–400 °C, was used to identify the catalytic activity of SnO 2 based catalysts. Results are discussed on the bases of the electrical changes accompanying variation of the active phase content. The conductance/capacitance of supported samples evidenced the reciprocal influence of the support and of the guest oxide.