Ruthenium-Loaded Heteroatomic Zeolite for Selective Hydrodeoxygenation Reaction in Aqueous Medium.

Area of Science:

• Catalysis
• Materials Science
• Green Chemistry

Background:

• Hydrodeoxygenation (HDO) is vital for upgrading bio-oil.
• Selective cleavage of C(sp2)-OH bonds in lignin derivatives under aqueous conditions is challenging.

Purpose of the Study:

• To develop a highly efficient catalyst for aqueous-phase HDO of lignin-derived substrates.
• To achieve selective conversion of lignin derivatives to aromatic chemicals while preserving aromaticity.

Main Methods:

• Synthesis of a heteroatomic zeolite catalyst (RuFA/SAPO-34-Nb) with few-atom Ru clusters on a Nb(V)-modified SAPO-34 framework.
• Characterization using synchrotron X-ray diffraction, X-ray absorption spectroscopy, and inelastic neutron scattering.
• Theoretical modeling to elucidate the catalytic mechanism.

Main Results:

• Quantitative conversion of creosol to toluene (99.2% conversion, 99.6% selectivity) under mild conditions (250 °C, 7 bar H2).
• Demonstrated selective cleavage of C(sp2)-O bonds without aromatic ring saturation.
• Elucidation of a cooperative mechanism involving Nb(V) sites and Ru clusters.

Conclusions:

• The RuFA/SAPO-34-Nb catalyst offers a promising strategy for aqueous-phase HDO catalysis.
• This work provides a general approach for designing bimetallic zeolite catalysts for lignin valorization.
• Advances sustainable biorefinery processes by converting lignin to value-added aromatic chemicals.