Methane steam reforming (MSR) consists of two overall reactions, the reaction of methane and water producing hydrogen and carbon monoxide and the water gas shift reaction. Due to its significance in hydrogen production, extensive experimental and modeling kinetic studies have been reported in the literature. However, the kinetics providing detailed information of elementary reaction steps, namely micro-kinetics, has not been definitely addressed. Employing the theory of Reaction Route Networks, recently developed by Fishtik et al. [1] and using UBI-QEP [2] method coupled with transition state theory to predict elementary reaction step kinetics, a detailed microkinetic model of steam and dry reforming of methane has been developed on Ni(111) [3].

The standard reference on the mechanism kinetics of MSR is that of Xu and Froment, who proposed a 13 step mechanism [4]. Based on the assumption of rate limiting steps, Xu and Froment provided rate expressions with fitted parameters. Our detailed micro-kinetic mechanism of steam and dry reforming of methane on Ni(111) has been developed by adding steps, pertinent to carbon formation on the catalyst, to the Xu and Froment mechanism. Employing the theory of Reaction Route Networks [1], the mechanism was converted into a graph-theoretic network and a corresponding electric circuit-analogy, it has been further analyzed, simplified and reduced [3].

References: 1. Fishtik, I., Callaghan, C. A., Datta, R., J. Phys. Chem. B 108, 5671 (2004). 2. Shustorovich, E., and Sellers, H., Surface Science Reports 31, 1 (1998). 3. Liu, J., Kinetics, catalysis and mechanisms of methane steam reforming, M.S. Thesis, Worcester Polytechnic Institute, Jan (2007). 4. Xu, J., and Froment. G. F., AIChE 35, 88 (1989).

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