Characterization of supported metal oxide particles by variable angle x-ray photoelectron spectroscopy

Abstract

The preliminary results of a newly developed method to determine the particle size distribution of a solid supported dispersed phase are presented. It is based on a modification of a theoretical model proposed by Kuipers et al. and employed intensity data obtained using variable angle x-ray photoelectron spectroscopy (VAXPS). The heart of the computer program generated is a nonlinear least-squares algorithm based on the Marquardt-Levenberg procedure. The test calculations show that the average particle size diameter of particles in heterogeneous catalysts can be determined with an accuracy of 16%. Comparison of particle size distributions obtained from transmission electron microscopy and VAXPS shows significant differences, which can partly be explained by fundamental differences of the techniques. The method appears to be a promising approach, which we hope to improve in the near future.