Adsorption and hydrogenation of pyridine and pyrrole on NiMoS: an ab initio density-functional theory study

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• 作者：Sun ; Mingyong ; Nelson ; Alan E. ; Adjaye ; John
• 关键词：Pyridine ; Pyrrole ; Adsorption ; Hydrodenitrogenation ; Hydrogenation ; Density-functional theory
• 刊名：Journal of Catalysis
• 出版年：2005
• 出版时间：April 1, 2005
• 年：2005
• 卷：231
• 期：1
• 页码：223-231
• 全文大小：785 K

文摘

The adsorption and first-step hydrogenation of pyridine and pyrrole on the Ni-promoted (andle=V-WA-A-W-WZ-MsSAYWW-UUW-U-AAWCVVDYZW-AAWBUWYZZW-WCDCVWEUE-WZ-U&_acct=C000050221&_version=1&_userid=10&md5=34ac4d882172830f36d696518061807b"">) edge of MoS₂ are studied with the use of periodic density-functional theory calculations under generalized gradient approximation. This study represents the first systematic theoretical investigation of the energetics and reaction pathways of possible reaction mechanisms (Langmuir–Hinshelwood, Eley–Rideal) for the hydrogenation of pyridine and pyrrole on the NiMoS catalyst edge plane. The most stable configuration for adsorbed pyridine on the Ni-edge surface is with the molecular plane perpendicular to the surface through NNi bonding. Pyrrole preferably interacts with the surface through the bonding of an α-carbon to a nickel site with the molecular plane flat on the surface. For the hydrogenation of pyridine via a Langmuir–Hinshelwood mechanism, the lowest-activation-energy reaction pathway involves hydrogen from adsorbed H₂S; for pyrrole the lowest-activation-energy reaction pathway involves hydrogen from the SH groups at the edge of the MoS₂ (0001) basal plane. Eley–Rideal reaction pathways involving gas-phase pyridine or pyrrole and surface hydrogen species require very low activation energy, and thus the dissociation of hydrogen on the catalyst surface would be the rate-determining step under these reaction conditions.