title: Catalytic Reaction Rates Controlled by Metal Oxidation State: C-H Bond Cleavage in Methane over Nickel-Based Catalysts.
abstract: The role of low concentrations of carbon complexes in hydrocarbon decomposition over transition metal surfaces has been a topic of much debate over the past decades. It is also a mystery as to whether or not electric fields can enhance hydrocarbon conversion in an electrochemical device at lower than normal reforming temperatures. To provide a "bottom-up" fundamental insight, C-H bond cleavage in methane over Ni-based catalysts was investigated. Our theoretical results show that the presence of carbon or carbide-like species at the interface between the Ni cluster and its metal-oxide support, as well as the application of an external positive electric field, can significantly increase the Ni oxidation state. Furthermore, the first C-H bond cleavage in methane is favored as the local oxidation state of Ni increases. Thus, the presence of a low concentration of carbon species, or the addition of a positive electric field will improve the hydrocarbon activation process.
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164, USA.
authors.forename: Fanglin
authors.initials: F
authors.lastname: Che
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164, USA.
authors.forename: Su
authors.initials: S
authors.lastname: Ha
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164, USA.
authors.forename: Jean-Sabin
authors.identifier: 0000-0003-0931-4869
authors.initials: JS
authors.lastname: McEwen
keywords: C-H bond activation; carbon species; electric fields; methane; nickel