Design of Multicationic Copper-Bearing Layered Double Hydroxides for Catalytic Application in Biorefinery

Ethanol has been used as a renewable hydrogen-donor in the conversion of a lignin model molecule in subcritical conditions. Noble metal-free porous mixed oxides, obtained by activation of Cu-Ni-Al and Cu-Ni-Fe layered double hydroxide (LDH) precursors, have been used as heterogeneous catalysts for Meerwein-Ponndorf-Verley (MPV) hydrogen transfer and further hydrogenation by ethanol dehydrogenation products. Both the Cu/(Cu+Ni) ratio and the nature of the trivalent cation (Al or Fe) affect the activity of the catalysts, as well as the selectivity towards the different steps of the hydrogenation reactions and the cleavage of lignin-like phenylether bonds. Accounting for the peculiar behaviour of Cu2+ and M(III) cations in the synthesis of LDHs, the coprecipitation of the precursors has been monitored by titration experiments. Structural and textural properties of the catalysts are closely related to the composition of the LDH precursors.

Automated summary

Ethanol is used as a renewable hydrogen-donor for the conversion of a lignin model molecule. Noble metal-free porous mixed oxides derived from Cu-Ni-Al and Cu-Ni-Fe layered double hydroxide (LDH) precursors act as heterogeneous catalysts for the hydrogen transfer and hydrogenation reactions. The activity and selectivity of the catalysts are influenced by the Cu/(Cu+Ni) ratio and the trivalent cation (Al or Fe), as well as the cleavage of lignin-like phenylether bonds. The composition of the LDH precursors has a significant impact on the structural and textural properties of the catalysts.