Production of liquid fuels via catalytic transfer hydrogenation promoting lignin depolymerization on modified Y zeolite: Formic acid as a continuous hydrogen source

• Published in: Energy conversion and management Vol. 302; p. 118144
• Main Authors: Zhang, Xia, Jiang, Yihang, Li, Wenzhi, Zhu, Leyu, Wang, Liqun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.02.2024
• Subjects: Catalytic transfer hydrogenation; Hydrodeoxygenation; Kraft lignin; Liquid fuels; Synergistic catalysis; Synergistic catalysis; Hydrodeoxygenation; Liquid fuels; Catalytic transfer hydrogenation; Kraft lignin
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2024.118144

[Display omitted] •Proposed a technology for lignin depolymerization under hydrogen-free condition.•L-acid site and the hydrogenation site enhanced the depolymerization efficiency.•The monomer yield reached 38.09 wt%, which has rarely been reported.•It solved the challenge of traditional hydrogenation technology of lignin. Efficient depolymerization of lignin to produce valuable liquid fuels and phenolic compounds is essential to improve the effective utilization and contribution towards energy sustainability. However, challenges arise due to its complex three-dimensional structure, the inclination of intermediates to condense, and the excessive dependence of depolymerization reaction on high-pressure hydrogen. Herein, a novel Ni- and Zn- modified Y-zeolite (Ni1Zn1/HYa) was prepared to attain effective lignin conversion under conditions devoid of exogenous hydrogen, by utilizing formic acid as an in situ hydrogen donor. Ni1Zn1/HYa selectively activated and decomposed formic acid, continuously releasing H2 for lignin depolymerization. It stabilized active intermediates and inhibited condensation through synergistic interactions between Lewis acid (L-acid) and hydrogenation active sites, resulting in a depolymerization rate that effectively competes with the condensation rate. Following a 24 h reaction at 290 °C, the yields of liquid products and petroleum ether soluble (PES) reached 91.70 % and 67.74 %, respectively, without any coke production. Further, the higher heating value increased from 25.41 MJ kg−1 to 32.47 MJ kg−1.