Co-impregnating binary Cobalt/Molybdenum/Alumina (CoMo/Al 2 O 3 ) catalyst with addition of ethylenediamine was studied for carbonization, sulfidation and hydrodesulfurization using experimental methods. In order to understand the mechanism of carbonization of active phases, theoretical CoMo/Carbon models were produced using density functional theory (DFT) methods. Results from carbonization of the organic component indicate that the formation of support-like carbon species provoke dispersion of active particles and reduce interaction with support at the active sites (Co, Mo), thus enhancing the HDS activity. Geometrical optimization by DFT shows that a carbide-like Co-Mo-C structures are more stable, which can be formed by a simultaneous carburization and sulfidation at unsaturated S or Mo edge of (Co)MoS x slab with CH 3 SSCH 3 as both carbon and sulfur source.Until now, the issues concerning the carbonation of HDS catalysts are still in debate. For systematically and explicitly elucidating the roles played by carbon species, we designed a research plot. We firstly identified the carbon species on HDS catalyst, investigated the formation mechanism of each carbon species, and then illustrated the effect of these carbon species on the HDS activity. In this work, experimentally, CoMo catalysts were prepared with addition of EN, and then sulfided with organic agents (thiophene and DMDS). We focus our attention to the carbon species. In order to correlate experimental results a series of computer assisted DFT calculations were performed, investigating the carburization at the "Co-Mo-S" active sites at the atomic level. Experimental and computational details Catalyst preparationThe catalysts were prepared by impregnating γ-Al 2 O 3 with NH 3 aqueous solution of Co(NO 3 ) 2 ·6H 2 O, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and EN, followed by drying at 110 o C for 12 h. The catalysts with the EN/Co molar ratio of 1 and 2 were denoted as CoMo(EN1) and CoMo(EN2) respectively. Comparison catalyst was prepared by calcining CoMo(EN1) under air at 450 o C for 4 h to remove EN; it was represented as CoMo. The loadings of CoO and MoO 3 for all catalysts (after calcinations) were 3.2 and 16 wt%, respectively. Catalyst sulfidation and HDS testThe sulfidation and HDS tests were carried in a fixed bed tubular flow reactor with an inner

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Among the adopted zeolites, SAPO-11 exhibits exceptional shape-selectivity and stability to synthesize 2,6-dimethylnaphthalene from methylation of naphthalene, due to the special pore structure of SAPO-11 which inosculated better with 2,6-dimethylnaphthalene than with 2,7-dimethylnaphthalene.