Electrocatalytic Lignin Valorization via Enhanced H₂O₂ Generation Using a MWNCT-Modified Gas Diffusion Electrode

Area of Science:

• Sustainable chemistry
• Electrocatalysis
• Materials science

Background:

• Lignin valorization is key for sustainable chemical production.
• Electrocatalytic methods offer mild conditions but face efficiency challenges.
• Oxygen reduction reaction (ORR) is crucial for generating hydrogen peroxide (H2O2).

Purpose of the Study:

• To develop efficient gas diffusion electrodes (GDEs) for electrocatalytic lignin valorization.
• To enhance hydrogen peroxide (H2O2) generation via the two-electron ORR pathway.
• To achieve high selectivity and yield in converting lignin to valuable aromatic compounds.

Main Methods:

• Fabrication of GDEs modified with few-layer graphene (GR) and multi-walled carbon nanotubes (MWCNT).
• Electrochemical characterization of modified GDEs for ORR performance.
• Electrochemical depolymerization of lignin using optimized MWCNT-GDEs.
• Analysis of reaction products to determine yield and selectivity.

Main Results:

• MWCNT-modified GDE showed superior surface area and conductivity.
• Achieved over 80% selectivity for H2O2 production via the two-electron ORR pathway.
• Electrochemical lignin depolymerization yielded 72.3% low-molecular-weight aromatic compounds in 1 hour.
• Demonstrated exceptional electrode durability over ten consecutive cycles.

Conclusions:

• MWCNT-modified GDEs are highly effective for electrocatalytic lignin valorization.
• In-situ H2O2 generation using these electrodes enables efficient production of aromatic chemicals.
• This approach offers a sustainable and scalable route for lignin upgrading.