CHARACTERIZATION OF CARBON AND ALUMINA SUPPORTED MOLYBDENUM SULFIDE CATALYSTS BY MEANS OF DYNAMIC OXYGEN CHEMISORPTION AND THIOPHENE HYDRODESULPHURIZATION ACTIVITY
Dynamic oxygen chemisorption measured in situ at 333 K and thiophene hydrodesulfurization were used to study the quantity and specific activity of catalytic sites present in sulfided Mo/C and Mo/nu-A1-20-3 catalysts. The molybdenum sulfide phase in the Mo/C catalysts was found to possess a high density of only one type of site with a high turnover frequency. Comparison of particle size data, obtained from XPS measurements, with oxygen chemisorption measurements indicated that 4/5 or 2/5 (according to the model) of the molybdenum surface atoms in the Mo/C catalysts can be regarded as potential sites. The nu-A1-20-3 supported molybdenum phase had a lower site density and different types of sites seemed to be present at low and high molybdenum concentration. The decline in activity with run time of both Mo/C and Mo/nu-Al-20-3 catalysts was not reproduced by the oxygen chemisorption capacities. Thus initial deactivation can not be caused by sistering of the active phase or by pore blocking.
Bibliographic Reference: 8TH INTERNATIONAL CONGRESS ON CATALYSIS, BERLIN-WEST (GERMANY), JULY 2-6, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31534 ORA
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Record Number: 1989122078000 / Last updated on: 1987-01-01
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