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Interface Effects in Hydrogen Elimination Reaction from Isopropanol by Ni13 Cluster on θ‑Al2O3(010) Surface

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journal contribution
posted on 2017-01-26, 00:00 authored by Andrey Lyalin, Ken-ichi Shimizu, Tetsuya Taketsugu
We present results of theoretical investigation on catalytic hydrogen elimination from isopropanol (C3H8O) by free and θ-Al2O3(010)-supported Ni13 cluster. The specific role played by the perimeter interface between the nickel cluster and alumina support is discussed. It is demonstrated that dehydrogenation of C3H8O on the free Ni13 cluster is a two-step process with the first hydrogen elimination from the alcohol hydroxyl group, followed by C–H bond cleavage. Our calculations show that H elimination from OH group of C3H8O to Ni13 cluster is the rate-determining step with the barrier of 0.95 eV, while the C–H bond cleavage requires overcoming the barrier of 0.41 eV. In the case of Ni13 cluster supported on θ-Al2O3(010) the isopropanol molecule adsorbs on top of the surface Al atom in the close vicinity of the nickel cluster, which results in considerable decrease in barrier for H elimination due to formation of the complementary adsorption sites at the metal/support interface. It is demonstrated that intermediate formation of the Ni–C bond considerably promotes C–H bond cleavage. The described mechanism provides fundamental understanding of the process of the oxidant-free catalytic hydrogen elimination from alcohols on supported nickel clusters and can serve as a tool for rational design of novel type of nanocatalysts based on abundant noble-metal-free materials.