Exploring the hydrodeoxygenation of lignin β-O-4 dimer model compound and bio-oil by DFT and experimental studies

• Dimer model compound HDO process over Ru catalyst is explored by DFT and experiments. • Adsorption of 2-Phenylethyl phenyl ether (PPE) on Ru (0001) surface is discussed. • PPE on Ru (0001) surface reaction pathway is investigated. • Ru/Nb 2 O 5 catalyst is employed in HDO of PPE and real bio-oil. Hydrodeoxygenation (HDO) is a pivotal process in the efficient utilization of biomass, with ruthenium (Ru) emerging as a highly effective catalyst for this reaction. A dimer model compound, more representative of bio-oil oligomers than monomers, was used to explore the HDO mechanism over a Ru catalyst through both density functional theory (DFT) calculations and experimental studies. Initially, the adsorption of 2-Phenylethyl phenyl ether (PPE) was examined through DFT, leading to the determination of an optimized structure. Subsequent calculations of the HDO reaction pathways on the Ru (0001) surface revealed that the β-O-4 linkage cleavage occurred with significantly low activation energy. For the experimental study, a Ru/Nb 2 O 5 catalyst was synthesized using wet impregnation method. Characterization of this catalyst through scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed its congruence with the DFT model. The catalytic performance of Ru/Nb 2 O 5 was evaluated in the PPE HDO process, where it demonstrated high efficiency. The applicability of the Ru/Nb 2 O 5 catalyst was extended to a real lignin bio-oil so as to further assess its effectiveness. This research provides a systematic study on PPE HDO over a Ru catalyst, illustrating the potential of using dimer model compounds in HDO mechanism investigations and the promising capabilities of Ru-based catalysts.