Density functional theory studies of methane dissociation on anode catalysts in solid-oxide fuel cells: Suggestions for coke reduction

• Published in: Journal of catalysis 2007-04, Vol.247 (1), p.20-33
• Main Authors: Galea, Natasha M., Knapp, Daniel, Ziegler, Tom
• Format: Article
• Language: English
• Subjects: Alloy catalysts; Applied sciences; Carbon adsorption; Catalysis; Chemistry; Coke; Coking; Copper catalysts; Density functional theory; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; General and physical chemistry; Methane; Methane dissociation; Nickel catalysts; Nickel step-blocking; Reaction kinetics; Solid oxide fuel cells; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2006.12.021

We studied the dissociation of methane into adsorbed carbon and hydrogen atoms on various surfaces to gain insight into carbon coke formation on solid-oxide fuel cell anodes. Preferred adsorption sites and energies were calculated for CH x ( x = 0 , … , 3 ) and H on Ni and Cu (111) planar and (211) stepped surfaces, on Cu Ni and Cu Co surface alloys, and on Ni(211) surfaces with step edge sites blocked by Au- and S-promoter atoms. Transition states and kinetic barriers were calculated on Cu(111) and Cu(211) and on the S Ni(211) surface. Our results are in excellent agreement with existing experimental and theoretical studies, suggesting that copper anodes have very low activity and high resistance to coking, and that step-blocking on the nickel surface can increase the tolerance of nickel-based anodes to carbon coke formation.