Ideally selective oxidation reactions of organic reactants would be carried out using aerial O2 only. However, as the products of such reactions usually are more reactive than the reactants, one has to employ catalysts that provide lattice oxygen which is subsequently replenished (CC Chiu et al., 2015). MoVOx mixed-metal oxides are such a material which can be very selective for C-H activation in an oxidative dehydrogenation reaction (N Watanabe et al., 2006). C-H activation produces a hydrocarbon radical in proximity to the support. With the resulting hydrogen, an electron is transferred to the oxide (LL Zhao et al., 2014). Using cluster models and hybrid functionals, we modelled this transformation, studying in particular the fate of the electron transferred to the support. This reaction is particularly interesting when the hydrogen of the former C-H bond is transferred to an oxygen moiety in bridge position between V and Mo centers. Using a DFT+U approach with U values fitted to experiment (S Lutfalla et al., 2011), the electron is calculated to transfer preferentially to a Mo center, while in a hybrid DFT description the electron remains at the V center. Besides reporting the energetics of the preferred radical locations, we also discuss likely co-adsorbates, e.g., water, to explore their effect on the C-H activation.

Oxidative dehydrogenation at MoVOx materials: Understanding the electronic structure from various DFT approaches

254th National Meeting (2017)

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