The selective hydrogenation of furfural over intermetallic compounds with outstanding catalytic performance?

Green Chemistry Pub Date: 2019-05-28 DOI: 10.1039/C9GC01119F

Abstract

The selective hydrogenation of furfural (a biomass-derived platform compound, C[double bond, length as m-dash]O versus C[double bond, length as m-dash]C) is an important reaction for the production of chemical intermediates widely used in the polymer industry. Herein, we report three non-precious intermetallic compounds (IMCs) (Ni3Sn1, Ni3Sn2 and Ni3Sn4) derived from a layered double hydroxide (LDH) precursor, which are characterized by a highly uniform dispersion of IMC nanoparticles and display surprisingly improved catalytic performance toward the selective hydrogenation of furfural (C[double bond, length as m-dash]O) to furfuryl alcohol. In particular, the Ni3Sn2 IMC shows optimal catalytic behavior (conversion: 100%; selectivity: 99%), which exceeds that of reported non-precious metal catalysts and is even comparable to that of noble metal catalysts (e.g., Au, Pd and Pt). A combinative investigation based on in situ FT-IR, XANES and Bader charge studies verifies electron transfer from Sn to Ni, facilitating the activation of adsorption of the C[double bond, length as m-dash]O bond on the Ni top site, whilst inhibiting the adsorption of C[double bond, length as m-dash]C. Both experimental studies (in situ FT-IR and catalytic evaluations) and theoretical calculations (DFT calculations and microkinetic modeling) reveal a vertical adsorption configuration of furfural molecules over the Ni3Sn2 IMC, followed by the first hydrogenation at the carbon atom (the rate-determining step) and the second hydrogenation at the oxygen atom. This detailed study of the structure-selectivity relationship is substantiated by virtue of establishing the adsorption configuration of the substrate and the reaction pathway, which paves the way for the rational design and development of high-efficiency heterogeneous catalysts for selective hydrogenation reactions.

Graphical abstract: The selective hydrogenation of furfural over intermetallic compounds with outstanding catalytic performance
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