First-principles study on the selective hydrogenation of the C[double bond, length as m-dash]O and C[double bond, length as m-dash]C bonds of acrolein on Pt-M-Pt (M = Pt, Cu, Ni, Co) surfaces.

ABSTRACT

Selective hydrogenation of the C[double bond, length as m-dash]O and C[double bond, length as m-dash]C bonds of acrolein on Pt-M-Pt (M = Pt, Cu, Ni, Co) surfaces has been investigated with first-principles calculations to understand the trends of the activity and selectivity of the reaction. On the pristine Pt(111) surface, the results suggest that the production of allyl alcohol (a product of C[double bond, length as m-dash]O bond hydrogenation) is limited by its desorption, which results in the selective hydrogenation of the C[double bond, length as m-dash]C bond. On the other three bimetallic surfaces, the results show that the desorption of the product is no longer rate-limiting, and the reaction should be selective for the C[double bond, length as m-dash]O bond hydrogenation. Although the calculated trends of activity and selectivity agree well with the experiment, the absolute selectivity predicted on the bimetallic surfaces is in contrast with existing experiments. Therefore, other effects such as the steric effect and reactions at other types of active sites may need to be investigated. On the other hand, the scaling relation analysis shows that the formation free energies of the intermediates, except for H, scale well with that of the adsorbed acrolein. This suggests that modifying the binding of H on the surface may be another dimension for the design of more efficient catalysts for the active and selective hydrogenation of the C[double bond, length as m-dash]O bond of acrolein.