The dehydrogenation of ethanol into acetaldehyde was theoretically studied on alkaline earth metal oxides (XO)<sub>12　 </sub>(X=Mg,Ca,Ba) (100) surface with different coordination numbers, which are here denoted as X-3, X4, and X-5 according to the coordination number. All calculations were executed by density functional theory (DFT) basis method.<br/>The adsorption energy of ethanol and the activation energy of dehydrogenation were listed in Table 1. It was found that the reactivity of dehydrogenation depends on coordination number. No dehydrogenation occurred on X-5 site. The dehydrogenation was found to occur on both X-3 and X-4 sites. Ethanol was sequentially dehydrogenated into acetaldehyde. First dehydrogenation occurred by extracting H atom from OH group and second dehydrogenation subsequently proceeded via H atom extraction from ethyl group. Both dehydrogenations on X-4 site showed dissociative adsorption of ethanol. It means the activation energy on X-4 site is the lowest and dominant active site is alkaline earth metal site with 4 coordination number. The order of adsorption energy was BaO &gt; CaO &gt; MgO, and the order of activation energy was MgO &gt; CaO &gt; BaO. BaO had the lowest energy gap between LUMO of ethanol and HOMO of BaO. These results showed that BaO is the most reactive for dehydrogenation of ethanol.

DFT study of dehydrogenation of ethanol on alkaline earth metal oxides

249th National Meeting (2015)

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