Ambient-pressure and low-temperature upgrading of lignin bio-oil to hydrocarbons using a hydrogen buffer catalytic system


Catalytic hydrodeoxygenation is an essential step for bio-oil upgrading. However, hydrodeoxygenation usually requires a high hydrogen pressure and high temperature due to the good stability of the C–O bonds. Here we report an effective multiphase hydrodeoxygenation of lignin-based bio-oil at temperatures <100 °C and hydrogen pressures <1 atm using a synergetic catalyst system that consists of a low redox potential H4SiW12O40 (SiW12) and suspended Pt-on-carbon (Pt/C) particles. We propose that SiW12 plays three critical roles in bio-oil hydrodeoxygenation. First, it quickly oxidizes the H2 gas to form reduced SiW12 in the presence of Pt/C. Second, it transfers both electrons and H+ ions to the bulk phase to form active H* or H2 on the Pt/C surface. Third, the formation of the oxonium ion in a SiW12 superacid solution reduces the deoxygenation energy. The SiW12-enhanced proton-transfer hydrodeoxygenation mechanism is supported by density functional theory computations. As a result of the hydrogen buffer and acidic effect, up to a 90% yield of hydrocarbons (cyclohexane, benzene and their derivatives) was achieved from the hydrodeoxygenation of phenol and its derivatives.

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Fig. 1: Illustration of hydrogen-buffer-improved bio-oil upgrading.
Fig. 2: The hydrogen buffer effect and HDO performance of the SiW12 and Pt/C catalyst system.
Fig. 3: HDO of phenol and guaiacol.
Fig. 4: Proposed mechanism of SiW12-induced HDO.
Fig. 5: Upgrading of different functional-group-substituted compounds under mild conditions.
Fig. 6: Three possible pathways for defunctionalization of the –OCH3 group using anisole as a model compound.

Data availability

The authors declare that the data supporting the findings of this study are available in the Article and Supplementary Information. Source data are provided with this paper.


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W.L. thanks the RBI at Georgia Tech for scholarship support.

Author information




Y.D. and W.L. conceived the project and designed the experiments. W.L. performed the electrochemical measurement and HDO experiments. W.S. and W. Yang helped with the HDO experiments and product analysis by GC. W. You and W.L. conducted the DFT calculations of proton-induced mechanisms. A.K. performed GC–mass spectrometry analysis of the HDO products. Y.G. performed the catalyst characterizations.

Corresponding author

Correspondence to Yulin Deng.

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Supplementary information

Supplementary Information

Supplementary Tables 1–5, Figs. 1–40 and refs. 1–55.

Supplementary Data

Source data for the TOFs of hydrocarbon generation during the phenol hydrodeoxygenation with different Pt-to-phenol ratios.

Source data

Source Data Fig. 3b

Source data for hydrodeoxygenations of phenol (at 75 °C) and guaiacol (at 95 °C) using N2 and H2 mixing gas (total pressure 1 atm).

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Liu, W., You, W., Sun, W. et al. Ambient-pressure and low-temperature upgrading of lignin bio-oil to hydrocarbons using a hydrogen buffer catalytic system. Nat Energy 5, 759–767 (2020).

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