Fabrication of hierarchical flower-like NiMo bimetallic catalyst for valorization of biomass platforms

Abstract

The rational design of catalysts with 3D open structures is vitally important to enhance catalytic performance through exposing the active sites. Herein, the hierarchical flower-like Ni-Mo bimetallic catalyst was constructed by using levulinic acid to synthesize γ-valerolactone as the template reaction and nitrogen-rich dual ligand MOF as the self-sacrificial template. Benefiting from the anchoring effect of N–C defects, the Ni-Mo bimetallic component was uniformly dispersed on the petal-shape nanosheets. The characterization results confirmed the doped Mo facilitated the formation of NiMo-Nx and MoO2 sites, and thus improved the dispersion of Ni species and the acidity of the catalyst. Density Functional Theory (DFT) calculations results confirmed that NiMo-Nx was more conducive to the dissociation of H2 than Ni and NiMo species. And, Ni-MoO2 interface could facilitate the activation and cleavage of the C–O in carbonyl group of levulinic acid. The synergy between the hydrogenation sites (NiMo-Nx) and the Lewis acid sites (Ni-MoO2 interface) enabled the catalyst excellent performance for the valorization of levulinic acid to γ-valerolactone in aqueous phase. In addition, the reaction mechanism was given according to the reaction results and DFT calculation results.