Effect of pore size of MgO-templated porous carbon electrode on immobilized crosslinked enzyme–mediator redox network

Magnesium oxide templated porous carbon (MgOC) is a promising material as an enzyme electrode platform. Herein, a flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) and thionine were immobilized using a crosslinker, and the applicability of MgOC with various pore sizes as a platform was investigated. Among the pores of MgOC, the novel designed FAD-GDH/thionine network generated a 1.1 mA cm−2 catalytic current at 100 nm pore size, demonstrating a significantly improved glucose supply and a thin redox composite layer was formed within the nanostructured material. At low loading, the catalytic current is independent of the pore size; however, at high loading, a varied catalytic current is achieved for the different MgOC pore sizes. Further, the stability was improved of porous platform compared to the glassy carbon (GC) electrode. Additionally, a glucose/O2 biofuel cell is constructed with FAD-GDH/thionine on porous MgOC and non-porous GC as an anode, and mediated bilirubin oxidase as a cathode. A remarkably high electricity generation efficiency (0.23 mW cm−2 μg−1 of FAD-GDH) is shown on a porous electrode platform than non-porous and a previously reported immobilized FAD-GDH-based anode. These results demonstrate the potential of porous MgOC as an anode for a novel FAD-GDH/thionine network toward electricity generation.