Membraneless glucose/O2 microfluidic enzymatic biofuel cell using pyrolyzed photoresist film electrodes

Abstract

Biofuel cells typically yield lower power and are more difficult to fabricate than conventional fuel cells using inorganic catalysts. This work presents a glucose/O₂ microfluidic biofuel cell (MBFC) featuring pyrolyzed photoresist film (PPF) electrodes made on silicon wafers using a rapid thermal process, and subsequently encapsulated by rapid prototyping techniques into a double-Y-shaped microchannel made entirely of plastic. A ferrocenium-based polyethyleneimine polymer linked to glucose oxidase (GOx/Fc-C₆-LPEI) was used in the anode, while the cathode contained a mixture of laccase, anthracene-modified multi-walled carbon nanotubes, and tetrabutylammonium bromide-modified Nafion (MWCNTs/laccase/TBAB-Nafion). The cell performance was studied under different flow-rates, obtaining a maximum open circuit voltage of 0.54 ± 0.04 V and a maximum current density of 290 ± 28 μA cm⁻² at room temperature under a flow rate of 70 μL min⁻¹ representing a maximum power density of 64 ± 5 μW cm⁻². Although there is room for improvement, this is the best performance reported to date for a bioelectrode-based microfluidic enzymatic biofuel cell, and its materials and fabrication are amenable to mass production.