Bimetallic W1V3Ox catalyzed selective hydrodeoxygenation of lignin to valuable aromatic chemicals

The W ₁ V ₃ Oₓ catalyst can catalyze the depolymerization of lignin into aromatic compounds in cyclohexane under H 2 atmosphere. • The W 1 V 3 Ox catalyst has weak and medium acidic sites that promote C O bond hydrogenation and deoxidation. • The Lewis acid sites played a critical role in the cleavage and hydrogenation of C–C bonds. • Raman indicated W and V interacted in the form of V-O-W. • DFT showed V-O-W can activate the C O and C-C bonds. Efficient utilization of lignin resources are critical for sustainable development of human, but the selective conversion of lignin to valuable aromatic chemicals still faces challenges. Herein, a novel W 1 V 3 O x catalyst was designed and prepared via one-pot hydrothermal strategy, which exhibited high catalytic activity towards the hydrodeoxygenation (HDO) of oxygen-containing lignin models and dealkaline lignin. For the model compound, diphenylethanone achieved a conversion of 99.9% and total yields of 98.2% with diphenylethane as the dominant product (yield 84.1%, selectivity 84.2%). Other major byproducts included toluene (yield 9.9%, selectivity 9.9%), diphenylethylene (yield 2.4%, selectivity 2.4%), and methylcyclohexane (yield 1.8%, selectivity 1.8%) at 250 °C. Common oxygen-containing lignin models can be converted into corresponding aromatic compounds. This active catalyst was also applicable to dealkaline lignin upgradation. Using lignin macromolecules as the substrate, the yield of phenolic compounds from lignin reached 71.2%, the yield of aromatic hydrocarbons reached 12.3%, and the yield of saturated hydrocarbons reached 5.2%, with total conversion of lignin. The W 1 V 3 O x catalyst exhibited good recyclability in the HDO process for both diphenylethanone and lignin, observed after five continuous runs. Characterization results revealed that the synergistic effect between W and V increased weak and moderate strength acidic sites, which proved beneficial for activating and cleaving C O and C-C bonds. DFT calculation results indicated that the W 1 V 3 O x catalyst possessed Lewis acidity, which facilitated the activation of C O and C-C bonds in diphenylethanone through adsorption. The synergistic effect of W and V could lower the C α -C β bond energy barrier, thereby promoting the conversion of diphenylethanone and the depolymerization of lignin. The research provided a novel and efficient W 1 V 3 O x catalyst for lignin valorization. Download: Download high-res image (123KB) Download: Download full-size image The W₁V₃Oₓ catalyst can catalyze the depolyerization of lignin into aromatic compounds in cyclohexane under H 2 atmosphere with depolymerization degree of 99.9% and the yield of phenolic compounds from lignin reached 71.2%, the yield of aromatic hydrocarbons reached 12.3%, and the yield of saturated hydrocarbons reached 5.2%.