Document Type





metal; platinum; zeolite; absorption; article; catalyst; chemical composition; gas; mathematical analysis; temperature; X ray crystallography




Information about the metal phase in a supported-metal catalyst can be obtained using anomalous small-angle X-ray scattering (ASAXS). The difference between the scattering profiles for SAXS at two different wavelengths near the metal's absorption edge is essentially the scattering of the metal alone. Novel in situ ASAXS measurements are made on mordenite impregnated with platinum metal while the temperature and composition of gas in the sample cell are changed. Measurements are made 62 times during treatment of the catalyst. The metal particles are assumed to be randomly distributed spheres with N(R)dR = number of spheres with radii between R and R + dR. It is found that N(R) is always a monotonically decreasing function of R, and that the average value of R, obtained from N(R), decreases by a factor of two over the time (approximately 6 h) for which the system is observed.

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Copyright 2005 Journal of Applied Crystallography. This article may be downloaded for personal use only. Any other use requires prior permission of the author and Journal of Applied Crystallography.

The article may be found at doi:10.1107/S0021889805002165


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