Ru/Hβ catalyst prepared by the deposition-precipitation method for enhancing hydrodeoxygenation ability of guaiacol and lignin-derived bio-oil to produce hydrocarbons

Abstract

Recently hydrocarbons with high yield from the selective hydrodeoxygenation (HDO) of lignin-derived bio-oil under low temperature still encounters the great challenges. However, metal nanoparticles size and acid site can greatly influence the HDO activity of metal catalyst. Herein, the efficient bifunctional Ru/Hβ catalyst was prepared by modified deposition-precipitation (DP) method for the HDO reaction of guaiacol and catalytic isoproanolysis lignin-derived bio-oil. Notably, compared to the impregnated Ru3%/Hβ-25 catalyst, Ru3%/Hβ-25 (DP) catalyst exhibited the higher catalytic activity on the HDO of guaiacol, smaller Ru nanoparticles size, and more acid sites. It was observed that guaiacol can be completely converted to cyclohexane under 180 °C, 3 MPa H2, and 2 h in n-hexane. This Ru3%/Hβ-25 (DP) catalyst proved to be the good recyclability in the HDO reaction of guaiacol, the conversion decreased slightly to 82.3% and the yield of cyclohexane decreased to 71.2 mol% after four recycle times. Furthermore, this high active catalyst was also applied to the upgradation of bio-oil derived from the catalysis isoproanolysis of lignin in the organic phase. As a result, after the upgradation, bio-oil contained high relative content (RC) of hydrocarbons, including 42.99% cycloalkanes and 50.74% arenes, and oxygenated compounds of raw bio-oil were almost removed. Overall, during upgradation of raw lignin-derived bio-oil over Ru3%/Hβ-25 (DP) catalyst process, not only HDO reaction, but also cleavage of C-O bonds can be achieved in one-pot.