Green Hydrodeoxygenation of Biomass Pyrolysis Oil into Cycloalkanes Using Ni-Mo Nanoparticles Supported H-Mesoporous Beta Catalysts

Abstract

Significant challenges in upgrading biomass pyrolysis oil (BPO) involve directional cleavage of >C-O- linkages with high bond strength and the cascade hydrogenation of aromatic rings to prevent recondensation, leading to the production of cycloalkanes. We report the synthesis of H-mesoporous beta (HMB) supported Ni-Mo nanoparticles (NPs) catalysts (Ni-Mo/HMB) via a two-step synthesis strategy, which includes the in-situ reconstruction of mesopores and the uniform dispersion of bimetallic NPs under solvothermal conditions. The Ni-Mo/HMB catalyst effectively converted BPO to cycloalkanes under mild conditions, which was assignable to the synergistic effect between accessible Lewis acidic sites (LASs) and Ni-Mo hydrogen binding sites for catalyzing hydrodeoxygenation (HDO). The Ni-Mo/HMB with close distance of bimetallic Ni-Mo NPs and accessible LASs achieved mequinol to cyclohexane with selectivity of 100% at 140 oC for 2 h under 4 MPa initial hydrogen pressure (IHP). Correspondingly, BPO contains all heteroatom-containing organic species (including 92.4% OCOCs, 3.4% NCOCs, and 2.2% SCOCs) and 2.0% benzenes underwent catalytic HDO over 10Ni-3Mo/HMB at 140 oC for 16 h achieved the high yield of cycloalkanes (61.5%) and chain alkanes (CAs, 38.5%). In addition, first-principle show that 10Ni-3Mo/HMB for high catalytic activity from the active hydrogen species transfer within bimetallic Ni-Mo NPs and accessible LASs.

Keywords: Bifunctional catalysis, hydrodeoxygenation, Biomass pyrolysis oil, Bimetallic-acid sites, molecular simulation