Design of Laccase-Metal Organic Framework-Based Bioelectrodes for Biocatalytic Oxygen Reduction Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Biocatalysis

Background:

• Laccase and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) are established bioelectrocatalysts for oxygen reduction reactions (ORR).
• Metal-organic frameworks (MOFs) offer tunable porous structures for immobilizing biomolecules.

Purpose of the Study:

• To investigate the use of mesoporous iron(III) trimesate-based MOF, MIL-100(Fe), as an immobilization matrix for laccase and ABTS.
• To develop efficient biocathodes for ORR using this novel material.

Main Methods:

• Immobilization of ABTS within MIL-100(Fe) pores studied using micro-Raman spectroscopy, X-ray powder diffraction (XRPD), and N2 porosimetry.
• Electrochemical characterization of ABTS-MIL-100(Fe) modified electrodes.
• Immobilization of laccase onto the MIL-100(Fe)-ABTS matrix to create the Lac-ABTS-MIL-100(Fe)-CIE bioelectrode.
• Evaluation of the bioelectrode's performance in ORR.

Main Results:

• MIL-100(Fe) demonstrated excellent properties for immobilizing ABTS, enhancing charge transfer kinetics and ionic conductivity.
• The ABTS-MIL-100(Fe) matrix provided a stable and reproducible electrochemical response.
• The resulting Lac-ABTS-MIL-100(Fe)-CIE bioelectrode exhibited high electrocatalytic current density for ORR.
• The bioelectrode showed remarkable stability over three weeks.

Conclusions:

• MIL-100(Fe) is an effective and stabilizing matrix for laccase and ABTS immobilization for ORR biocathodes.
• The synergy between MIL-100(Fe) and laccase contributes to high catalytic efficiency in ORR.
• This work represents a significant advancement in laccase-based bioelectrocatalysts for oxygen reduction.