II International Symposium on Carbon for Catalysis ABSTRACTS

OP-I-22
RADIOISOTOPIC INVESTIGATION INTO THE ACTIVE SITE DYNAMICS OF
Co(Ni)Mo SULPHIDE CATALYSTS SUPPORTED ON Al 2 O 3 AND ACTIVATED
CARBON AND MODIFIED BY P AND F ADDITIVES
Kogan V.M.
N.D. Zelinsky Institute of Organic Chemistry RAS, Moscow, Russia
e-mail: vmk@ioc.ac.ru
The nature of the support has big effect on the formation and acting of sulphide catalyst
active sites (AS). Twoquestions are under consideration in the study:
1. The difference between support effects of Al 2 O 3 and activated carbon on the formation
and acting of the active phase of sulphide Co(Ni)Mo catalysts;
2. How support modification by P- and F-additives affects the AS acting.
Comparing Al 2 O 3 and activated carbon support effects
Hydrotreating catalysts prepared by loading of activated carbon with an active phase
(C-supported catalysts) are more active than conventional systems based on Al 2 O 3 . However,
there are some reasons that limited C-supported catalysts industrial application. In order to
understand the principles of functioning of the active phase on different supports, it is
necessary to study the transformations of organosulphur compounds on the surface of this
phase and to evaluate dynamic properties of the catalyst AS.
A tracer method enabled us to determine the number of surface SH groups, the number
and reactivity of AS, and correlate these data with the composition of the active phase of the
sulphide catalyst. The influence of the support (Al 2 O 3 and activated carbon) on the activity of
Mo, NiMo, and CoMo catalysts in thiophene hydrogenolysis is studied using 35 S as a tracer.
The carbon-supported catalysts have more AS than their Al 2 O 3 -supported counterparts, while
the turnover frequencies of these sites are similar. The turnover frequency of the AS depends
on the promoter content of the active phase and is support-independent. The active phase in
the C-supported catalysts is reduced to a greater extent than that in the Al 2 O 3 -supported
catalysts. Raising the Mo content increases the reduction of the active phase in both the
Al 2 O 3 - and C-supported catalysts. Thiophene desulphurization and hydrogenation of the
resulting C 4 olefins take place at the same Mo sites. Tracer tests have demonstrated that the
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