Computational Investigation of the Thermochemistry and Kinetics of Steam Methane Reforming Over a Multi-Faceted Nickel Catalyst
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AbstractA microkinetic model of steam methane reforming over a multi-faceted nickel surface using planewave, periodic boundary condition density functional theory is presented. The multi-faceted model consists of a Ni(111) surface, a Ni(100) surface, and nickel step edge sites that are modeled as a Ni(211) surface. Flux and sensitivity analysis are combined to gain an increased understanding of the important reactions, intermediates, and surface facets in SMR. Statistical thermodynamics are applied to allow for the investigation of SMR under industrially-relevant conditions (e.g., temperatures in excess of 500 °C and pressures in excess of 1 bar). The most important surface reactions are found to occur at the under-coordinated step edge sites modeled using the Ni(211) surface as well as on the Ni(100) surface. The primary reforming pathway is predicted to be through C*+ O*→ CO*at high temperatures; however, hydrogen-mediated reactions such as C*+ OH*→ COH*and C.H.*+ O*→ CHO*are predicted to become more important at low temperatures. The rate-limiting reactions are predicted to be dissociative chemisorption of methane in addition to the aforementioned C-O addition reactions. © 2011 Springer Science+Business Media, LLC.
CitationBlaylock DW, Zhu Y-A, Green WH (2011) Computational Investigation of the Thermochemistry and Kinetics of Steam Methane Reforming Over a Multi-Faceted Nickel Catalyst. Top Catal 54: 828–844. Available: http://dx.doi.org/10.1007/s11244-011-9704-z.
SponsorsThe authors acknowledge the catalysis researchers at the Norwegian University of Science and Technology (NTNU), in particular Professors Anders Holmen and De Chen, for many helpful conversations. This work is funded, in part, through a collaboration with NTNU supported by StatoilHydro and the Norwegian Research Council. The National Science Foundation is also acknowledged for supporting D.W.B. through the Graduate Research Fellowship Program. In addition, the Norwegian Research Council and the National Science Foundation are acknowledged for support of D.W.B. through the Nordic Research Opportunity. This publication is also based on work supported, in part by King Abdullah University of Science and Technology (KAUST). The computations in this work have been supported in part by the National Science Foundation through TeraGrid resources provided by the NCSA, grant number TG-CHE080047. Finally, Yi-An Zhu acknowledges support by the Doctoral Fund of Ministry of Education of China (No. 200802511007).
JournalTopics in Catalysis