External Standard Method in Quantitative Analysis of Bimetallic Clusters (Supported Catalysts)

摘要

Quantitative phase analysis with the use of external standard was applied in studies of phase composition of bimetallic supported Pd - Au on silica catalysts. Due to the specificity of the catalyst studies and necessity of in-situ investigation the use of external standard was the only possibility to deal with the problem of phase composition. The external standard method has been modified by using as two external standards catalyst made of each of the metals ( on the same support) and appropriate estimation of the mass absorption coefficient of the catalyst can be applied. The results show that for the 10 wt % ( 70 at. % Pd - 30 at. % Au ) on silica catalyst there is significant amount of palladium undetectable by the XRD ( amorphous phase ) whereas for the 2 wt. % ( 25 at. % Pd - 75 at. % Au) on silica the amount of the X-Ray amorphous phase is much lower.