BIMETALLIC CATALYSTS CHARACTERIZATION BY NONISOTHERMAL AND ISOTHERMALMETHODS

TPR, TPD and pulse adsorption methods may be employed in the character ization of unsupported bimetallic catalysts. Correlation of the result s obtained by the three methods affords the determination of ''real'' TPR profiles i.e. the hydrogen consumption assigned to the reduction o f oxides or the lowering of the oxidation degree of the cations lying on the surface (modification of their valence). The results are applie d to Ni-Cr unsupported catalysts.