Important Issues on Crystal Size Measurement of Catalysts

Abstract

A large number of papers have been published on using HREM to characterize the crystal structure and defects of catalysts. While such work is important to advance the scientific understanding of catalysis, the bulk of daily analytical work of an industrial catalyst microscopist focuses on analyzing the morphological features of the catalysts. That is, to find out the shape, the size, and the distribution of various phases. in the case of heterogeneous catalysts, the same information is needed for the catalytic metal particles. Ultimately, the goals are to correlate the performance of the catalyst with the size and morphology of the phases or particles. These types of information are often critical element in a patent.

Unfortunately, very little attention has been paid to properly and quantitatively describe crystal shapi crystal size, and size distribution. It is common to find in the literature, statements such as “the crystal size of this sample was 0.5 microns” or “the sample contains elongated crystals of 0.5 microns”.