Synergistic Catalysis of Co-Zr/CNx Bimetallic Nanoparticles Enables Reductive Amination of Biobased Levulinic Acid

Bimetallic synergy and carbon–nitrogen doping can contribute to enhanced catalytic activity due to the strong electronic state and unique geometrical structure. In this work, a series of biomass-derived Co-M bimetallic C  N doped catalysts (Co-M@Chitosan-X; M = Zr, Ni, Fe, Cu, In; X denotes the molar percentage of M) are prepared via simple oil bath reflow and annealing. The Co-Zr@Chitosan-X catalysts are determined to contain alloys (Co-Zr), metal-carbon bonds (Co-C, Zr-C), metal-nitrogen bonds (Co-N, Zr-N), and metal oxides (Co 3 O 4 , ZrO 2 ) through a series of characterizations, in which graphite-coated alloys and metal oxides are found to be the catalytically active species. The doping of the second metal results in a significant enhancement for the number of active sites in the catalyst, and the d-band center is shifted toward a deviation from the Fermi energy level. Among the tested catalysts, Co-Zr@Chitosan-20 exhibits superior catalytic activity for the reductive amination of biobased levulinic acid to 5-methyl-2-pyrrolidone in 99.3% selectivity and 92.8% yield. This non-noble metal bimetallic synergistic catalytic protocol opens an avenue for efficiently producing biomass-derived nitrogenous chemicals.