A highly efficient buckypaper-based electrode material for mediatorless laccase-catalyzed dioxygen reduction

Area of Science:

• Electrochemistry
• Biomaterials Science
• Energy Conversion

Background:

• Mediatorless biofuel cells utilize redox enzymes like laccase for efficient oxygen reduction.
• Multi-walled carbon nanotubes (MWCNTs) are promising electrode materials due to their conductivity.
• Optimizing MWCNT structure is crucial for enhancing enzyme-electrode interactions and overall cell performance.

Purpose of the Study:

• To investigate buckypaper (BP) fabricated from MWCNTs as an electrode material for laccase-catalyzed cathodes.
• To evaluate the electrochemical performance of laccase-modified BP electrodes in oxygen reduction reactions (ORR).
• To compare the efficiency of BP-based electrodes with electrodes made from non-dispersed MWCNTs.

Main Methods:

• Fabrication of MWCNTs into mechanically stable, mesoporous buckypaper structures.
• Electrochemical characterization using galvanostatic polarization and potentiodynamic linear sweep voltammetry.
• Investigation of laccase adsorption and performance in oxygen-saturated buffer at pH 5.

Main Results:

• Buckypaper (BP) provides a highly dispersed, conductive, and mesoporous matrix for laccase immobilization.
• Laccase-modified BP electrodes exhibit a high open circuit potential (0.882 V vs. NHE).
• BP electrodes achieve high current densities (422±71 μA cm⁻²) and demonstrate a 68-fold improvement in mass activity compared to non-dispersed MWCNT electrodes.
• The electrodes show high tolerance to glucose, a common biofuel.

Conclusions:

• Buckypaper (BP) is an excellent electrode material for constructing mediatorless laccase cathodes for ORR in biofuel cells.
• The enhanced performance is attributed to reduced mass transfer limitations and improved electrical conductivity offered by the BP structure.
• BP-based electrodes represent a significant advancement for efficient and stable biofuel cell technology.