II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-22
pyrolysis and activation conditions. The adsorption characteristics of the activated carbons
produced from various agricultural by-products were found to be different and dependent on
the composition and structure of the raw materials. A principal part of micropores has radius
about 2 nm. The higher temperature of the carbonization leads to formation of a more fine
porous structure. The activated carbons loaded with the HPMo changed their surface and pore
distribution. The impregnated species close micropores of radius below 2 nm. The surface
area located in the narrowest micropores (smaller than 2 nm) will not be available for loading
with the active component. The 12-molybdophosphoric acid adsorbed strongly on activated
carbon, and the adsorption involved proton transfer from the HPMo to the carbon.
Results of thiophene conversion show that carbon surface, pore structure and catalytic
pretreatment by H 2 or H 2 S affect the evolution of hydrodesulfurization activity, which
depends on two simultaneously proceeding processes of active site formation and deactivation
[1]. Heterogeneity of the high carbon surface makes the distribution of the molybdenum
precursor in the catalyst non-homogeneous. The chemical state and surface composition of
oxide and used catalysts were revealed by X-ray photoelectron spectroscopy.
The flexibility of the carbon surface is the reason for the changes observed at every step
of catalyst preparation. Carbon peculiarities as well as catalyst activation affect initial
thiophene conversion. The results show that during H 2 S pretreatment of the sample. The
hydrogen sulfide reacts with Mo species as well as the carbon sites. The results have shown
that the activated carbon with appropriate meso/micropores ratio originated from apricot
stones is suitable as catalyst support.
Reference
1 A. Spojakina, N.G. Kostova, in Studies in Surface Science and Catalysis, “Catalysts
Deactivation”, vol. 88, B. Delmon, J.F. Froment (eds.), Elsevier, Amsterdam, 651 – 658
(1994).
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