Depolymerization of lignin to cycloalkanes using Lewis acid-enhanced bifunctional catalyst.

Area of Science:

• Catalysis
• Renewable Energy
• Biomass Conversion

Background:

• Lignin is a key biomacromolecule for renewable energy.
• Catalytic upgrading of lignin faces challenges in efficiency and selectivity.
• Adjusting acidic sites enhances hydrodeoxygenation (HDO) activity and product selectivity.

Purpose of the Study:

• To understand the structure-activity relationship of acid sites in catalysts.
• To construct synergistic Brønsted-Lewis acid sites for enhanced lignin upgrading.
• To develop an efficient heterogeneous catalyst for converting lignin bio-oil into alternative fuels.

Main Methods:

• Incorporation of Ni@NC active phase derived from metal-organic frameworks (MOFs) into HZSM-5.
• Creation of a synergistic Ni@NC-HZSM-5 composite catalyst with enhanced Lewis acid sites (LASs).
• Utilizing abundant Brønsted acid sites (BASs) in HZSM-5 for C-O bond cleavage.

Main Results:

• The Ni@NC-HZSM-5 catalyst exhibited enhanced strength and quantity of LASs.
• Facilitated cleavage of C_Ar-OCH₃ bonds in lignin oil.
• Promoted cleavage of C_Ar-OH bonds by BASs, achieving 98.50% conversion and 95.05% C₆₊ cycloalkane selectivity.

Conclusions:

• Synergistic action of dual acid sites in the composite catalyst enables efficient lignin oil upgrading.
• The developed catalyst offers a novel approach for converting lignin-based bio-oil into alternative fuels.
• This research contributes to the advancement of renewable energy technologies through efficient biomass conversion.