Coking mechanism and promoter design for Ni-based catalysts: A first principles study
Jing, X. Saeys, M.
Jing, X.
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Abstract
Based on a first principles study of the interaction of carbon with Ni(111), a new way is proposed to improve the coking resistance of Ni-based catalysts. Three forms of chemisorbed carbon - on-surface carbon atoms, bulk nickel carbide and graphene - are distinguished and their relative stability is studied. At low coverages, on-surface carbon atoms will diffuse to the Ni bulk until saturation at a C:Ni mole fraction of about 1:2. The formation of the carbide will affect the catalytic properties of Ni and might lead to catalyst deactivation. When the on-surface carbon can accumulate to high coverages, formation of a graphene overlayer becomes preferred, leading to surface blocking and catalyst deactivation. Boron was found to be a potential promoter to prevent coking of Ni-based catalysts by effectively blocking the diffusion of carbon into the Ni bulk. © World Scientific Publishing Company.
Keywords
Carbon chemisorption, Catalysis, Catalyst development, Coking, Density functional theory, Ni catalyst
Source Title
International Journal of Nanoscience
Publisher
Series/Report No.
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Date
2007-04
DOI
10.1142/S0219581X07004389
Type
Article