A NEW METHOD FOR ESTIMATING THE DISPERSITY OF DEPOSITED METALLIC NANOPARTICLES AND EXTENT OF THEIR INTERACTION WITH THE SUPPORT MATRICES

摘要

A new technical approach to investigation of heterogeneous catalysts with deposited metallic nanoparticles of the active component is suggested. Small-angle X-ray scattering (SAXS) patterns for powder samples of the support matrices with deposited metal particles (Pt, Pd and others) taken at varying density contrast are shown to provide essential information on the structure and dispersity of the active components and their interaction with the support surface, which allows an integral assessment of the formation of strong chemical binding of deposited metal to the support matrix. The measured structural characteristics are compared with data obtained by other physicochemical methods, in particular, transmission electron microscopy (TEM). The suggested technique is verified using mathematical models and applied to a real heterogeneous catalyst Pt/y-Al_20_3. The proposed method of SAXS data analysis makes it possible to reveal the formation of active sites in heterogeneous catalysts and optimize their preparation procedures.