First principles study of the coking resistance and the activity of a boron promoted Ni catalyst

Based on first principles density functional theory calculations, boron is proposed as a promoter to improve the coking resistance of Ni-based catalysts. Three types of chemisorbed carbon are distinguished on the Ni(1 1 1) surface: on-surface carbon is an important reaction intermediate, while both bulk carbon and graphene islands are unavailable for reaction and might lead to catalyst deactivation. Promotion by small amounts of boron was found to inhibit the formation of bulk carbon and weaken the on-surface carbon binding energy, possibly slowing down the formation of graphene islands. To confirm the activity of the boron promoted Ni catalyst, the activation energy for methane activation was calculated. A modest increase by 12 kJ/mol was found upon boron promotion. C) 2007 Elsevier Ltd. All rights reserved.