In situ anomalous small-angle X-ray scattering from metal particles in supported-metal catalysts. I. Theory

• Published in: Journal of applied crystallography 2005-02, Vol.38 (1), p.147-151
• Main Authors: Brumberger, H., Hagrman, D., Goodisman, J., Finkelstein, K. D.
• Format: Article
• Language: English
• Subjects: anomalous small-angle X-ray scattering; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; particle size distribution; Physics; Structure of solids and liquids; crystallography; supported-metal catalyst; X-ray diffraction and scattering; X-ray scattering (including small-angle scattering)
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S0021889804029000

A supported‐metal catalyst can be considered as a mixture of three homogeneous phases: support, void and metal. Information about the metal phase alone can be obtained using anomalous small‐angle X‐ray scattering (ASAXS), which requires measuring the SAXS for two different wavelengths near the metal's absorption edge. Herein, the conditions that must be obtained so that the difference between the two scattering profiles gives the scattering of the metal alone are presented. In a following contribution, the analysis will be applied to in situ ASAXS measurements made on mordenite impregnated with platinum metal while the temperature and composition of gas in the sample cell are changed. The metal particles are assumed to be randomly distributed spheres with N(R)dR being the number of spheres with radii between R and R + dR. From N(R) one can obtain the average value of R.