NiCu Nanoparticles for Catalytic Hydrogenation of Biomass-Derived Carbonyl Compounds

For heterogeneous supported catalysts, commonly, the adsorption of reactant molecules on the catalyst surface can significantly govern their activity and selectivity. In this paper, it was shown that surface oxygen-decorated bimetallic NiCu nanoparticles derived from ternary Ni–Cu–Al layered double hydroxide precursors exhibited better catalytic activity trends for the hydrogenolysis of biomass-derived carbonyl compounds compared with monometallic Ni or Cu ones. Specifically, bimetallic NiCu nanocatalyst achieved a maximum cyclopentanone yield of ∼89.5% in the aqueous phase hydrogenation of furfural. Based on a series of structural characterizations, catalytic experimental results, and density functional theory calculations, it was emphatically demonstrated that different catalytic behaviors might stem from the difference in the adsorption modes of the carbonyl group on the surfaces of monometallic Ni and bimetallic NiCu nanoparticles. It was deduced that due to the decoration of abundant surface oxygen species on bimetallic NiCu nanoparticles, the remaining exposed metal surface became η1(O)-type adsorption sites for the carbonyl group, different from the dominant η2(C, O) adsorption mode on monometallic Ni nanoparticles with less surface oxygen species. Most importantly, the present bimetallic NiCu nanoparticles as catalysts displayed superior catalytic performance in the hydrogenolysis of other carbonyl compounds (e.g., 5-hydroxymethylfurfural, benzaldehyde, and vanillin) to monometallic ones. Such surface oxygen decoration strategy endows bimetallic NiCu nanoparticles a great application potential in the catalytic conversions of biomass-derived carbonyl compounds.