Adsorption and dissociation of H₂ and H₂S on MoS₂ and NiMoS catalysts

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• 作者：Sun ; Mingyong ; Nelson ; Alan E. ; Adjaye ; John
• 关键词：Hydrotreating ; MoS₂ ; NiMoS ; Molecular modeling ; Density-functional theory ; Hydrogen sulfide ; Hydrogen ; Adsorption
• 刊名：Catalysis Today
• 出版年：2005
• 出版时间：July 15, 2005
• 年：2005
• 卷：105
• 期：1
• 页码：36-43
• 全文大小：421 K

文摘

The formation and stable structures of surface hydrogen species on unpromoted and nickel-promoted MoS₂ catalyst surfaces is studied by investigating the adsorption and dissociation of molecular hydrogen and hydrogen sulfide using periodic DFT calculations under generalized gradient approximation (GGA). On the stable andle=V-WA-A-W-AE-MsSAYZW-UUA-U-AAWCBEZUDZ-AAWWEDZYDZ-WCDAZECZY-AE-U&_acct=C000050221&_version=1&_userid=10&md5=0c2501b660a195978b1728695eb643b6""> Mo-edge, the dissociation of hydrogen with the formation of SH groups is an exothermic process and energetically most favoured. On a partially nickel-promoted andle=V-WA-A-W-AE-MsSAYZW-UUA-U-AAWCBEZUDZ-AAWWEDZYDZ-WCDAZECZY-AE-U&_acct=C000050221&_version=1&_userid=10&md5=020d497952542ee4acb5fbb2b3ae6528""> surface, the dissociation of molecular hydrogen to form a surface SH group and a MoH or NiH species is an endothermic process, and requires higher energy than on an unpromoted andle=V-WA-A-W-AE-MsSAYZW-UUA-U-AAWCBEZUDZ-AAWWEDZYDZ-WCDAZECZY-AE-U&_acct=C000050221&_version=1&_userid=10&md5=3a5c2ca6c1d221dfc1437373c9c466b0""> Mo-edge surface. On a fully promoted andle=V-WA-A-W-AE-MsSAYZW-UUA-U-AAWCBEZUDZ-AAWWEDZYDZ-WCDAZECZY-AE-U&_acct=C000050221&_version=1&_userid=10&md5=bc9ee2878fc3ad34f417e2d67a842707""> Ni-edge, associative adsorption of H₂ is exothermic, and dissociation to a pair of NiH and SH groups or two NiH species is endothermic. Hydrogen sulfide can be strongly adsorbed on the vacant nickel sites on the partially and fully nickel-promoted andle=V-WA-A-W-AE-MsSAYZW-UUA-U-AAWCBEZUDZ-AAWWEDZYDZ-WCDAZECZY-AE-U&_acct=C000050221&_version=1&_userid=10&md5=73c46d5aebd3f9bce3bf9e22f425963f""> Mo-edge surface, and surface SH groups can be formed by dissociation of adsorbed H₂S.