Modelling partial oxidation of methane over ZSM-5 and Mo6S8 catalysts
Conference contribution, 2017
Partial oxidation of methane is an interesting but difficult reaction. Experimentally, methane can be partially oxidized to methanol over metal-exchanged zeolites. In particular the ZSM-5 zeolite has been widely studied and has been shown to be active when exchanged with Cu, Ni, Co, and Fe [1-4]. A clear [Cu-O-Cu] 2+ candidate for active site for the methane-to-methanol reaction has been put forth for Cu-ZSM-5 [1,5]. A first question to ask is whether this [Cu-O-Cu] 2+ motif is generic and could work also with Cu interchanged with Ni, Co, or Fe. Herein, we employ first-principles calculations and micro-kinetic modelling to compare the performance of Ni, Co, and Fe in this motif to the Cu one. Our finding is that the methane-to-methanol reaction can only realistically happen for Cu on this motif. Thus, this particular motif can be excluded as an active site candidate for Ni-, Co-, and Fe-ZSM-5 . Another catalyst that is interesting for partial methane oxidation is the Mo6S8 cluster. However, instead of the methane-to-methanol reaction we use H2S as an oxidant and transform methane into hydrogen and CH3SH. Using electronic structure calculations and mean-field micro-kinetic modelling to study this reaction, we successfully capture the experimentally observed trend, i.e. that promoting the Mo 6 S 8 cluster with K increases the selectivity towards CH 3 SH, and Ni enhances the hydrogen formation .
 M. H. Groothaert, P. J. Smeets, B. F. Sels, P. A. Jacobs and R. A. Schoonheydt, J. Am. Chem. Soc., 127, 1394–1395 (2005).
 J. Shan, W. Huang, L. Nguyen, Y. Yu, S. Zhang, Y. Li, A. I. Frenkel and F. F. Tao, Langmuir, 30, 8558–8569 (2014).
 N. V. Beznis, B. M. Weckhuysen, and J. H. Bitter, Catal. Lett., 136, 52–56 (2010).
 E. V. Starokon, M. V. Parfenov, L. V. Pirutko, S. I. Abornev and G. I. Panov, J. Phys. Chem. C, 115, 2155–2161 (2011).
 J. S. Woertink, P. J. Smeets, M. H. Groothaert, M. A. Vance, B. F. Sels, R. A. Schoonheydt, and E. I. Solomon, Proc. Natl. Acad. Sci. U. S. A., 106, 18908–18913 (2009).
 A. A. Arvidsson, V. P. Zhdanov, P.-A. Carlsson, H. Grönbeck, and A. Hellman, Catal. Sci. Technol., 7, 1470, (2017).
 O. Y. Gutiérrez, L. Zhong, Y. Zhu, J. A. Lercher, ChemCatChem, 5, 3249–3259 (2013).
Partial methane oxidation