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Science 10 May 1985:
Vol. 228. no. 4700, pp. 717 - 719
DOI: 10.1126/science.228.4700.717
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Articles

Study by Synchrotron Radiation of the Structure of a Working Catalyst at High Temperatures and Pressures

M. BOUDART 1, R.A. DALLA BETTA 1, K. FOGER 1, D. G. LÖFFLER 1, and M. G. SAMANT 1

1 Department of Chemical Engineering, Stanford University, Stanford, California 94305

A relation among activity, composition, and structure was determined for a working catalyst by means of a stainless-steel reactor cell of novel design that permitted operation at temperatures and pressures similar to those in industrial reactors. Molybdenum K-edge x-ray absorption spectra were used to probe the structural environment of molybdenum in CoMoS/[unknown]-alumina catalysts while hydro-desulfurization of benzothiophene was proceeding at high temperature and pressure. For catalyst samples with different contents of cobalt, radial structure functions obtained from extended x-ray absorption fine structure data presented the same features as those obtained from the spectra of MoS2/[unknown]-alumina reference samples. Moreover, Mo-S and Mo-Mo coordination numbers were maximum for the sample with an atomic ratio of Co to (Co + Mo) of 0.33; this sample was also the most active catalyst tested.

Submitted on December 17, 1984
Accepted on February 13, 1985


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Edge Surfaces in Lithographically Textured Molybdenum Disulfide.
C. B. ROXLO, H. W. DECKMAN, J. GLAND, S. D. CAMERON,, and R. R. CHIANELLI (1987)
Science 235, 1629-1631
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A 6-GeV Storage Ring: An Advanced Photon Research Facility.
P. EISENBERGER (1986)
Science 231, 687-693
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