Abstract
Mediatorless and membraneless enzymatic biofuel cells (EBCs) employing new catalytic structure are fabricated. Regarding anodic catalyst, structure consisting of glucose oxidase (GOx), poly(ethylenimine) (PEI) and carbon nanotube (CNT) is considered, while three cathodic catalysts consist of glutaraldehyde (GA), laccase (Lac), PEI and CNT that are stacked together in different ways. Catalytic activities of the catalysts for glucose oxidation and oxygen reduction reactions (GOR and ORR) are evaluated. As a result, it is confirmed that the catalysts work well for promotion of GOR and ORR. In EBC tests, performances of EBCs including 150 μm-thick membrane are measured as references, while those of membraneless EBCs are measured depending on parameters like glucose flow rate, glucose concentration, distance between two electrodes and electrolyte pH. With the measurements, how the parameters affect EBC performance and their optimal conditions are determined. Based on that, best maximum power density (MPD) of membraneless EBC is 102 ± 5.1 μW · cm−2 with values of 0.5 cc · min−1 (glucose flow rate), 40 mM (glucose concentration), 1 mm (distance between electrodes) and pH 3. When membrane and membraneless EBCs are compared, MPD of the membraneless EBC that is run at the similar operating condition to EBC including membrane is speculated as about 134 μW · cm−2.
Highlights
As the possible enzyme catalysts, glucose oxidase (GOx) catalyzing glucose oxidation and laccase (Lac) catalyzing oxygen reduction have been considered[14,15]
We fabricate enzymatic biofuel cells (EBCs) system using (i) anode consisting of GA/[[GOx/PEI]2/carbon nanotube (CNT)] biocatalyst that is an enzyme structure based on our previous research for glucose oxidation reaction (GOR) and (ii) cathode consisting of three different biocatalysts including GA, Lac, PEI and CNT for oxygen reduction reaction (ORR)[22]
Regarding the activity of anodic catalyst, GOR occurring at flavin adenine dinucleotide (FAD) that was deep inside GOx molecules was investigated by CV measurements in N2-state and air-state (Fig. S1a)
Summary
As the possible enzyme catalysts, glucose oxidase (GOx) catalyzing glucose oxidation and laccase (Lac) catalyzing oxygen reduction have been considered[14,15]. Regarding PEI, it is charged positively, whereas enzyme molecules and CNT are negatively charged Such an opposite polarity makes bonding among them strong by electrostatic interaction[19,20]. Regarding cost and size of EBC system, optimizing role of membrane included in the EBC may be critical. We fabricate EBC system using (i) anode consisting of GA/[[GOx/PEI]2/CNT] biocatalyst that is an enzyme structure based on our previous research for glucose oxidation reaction (GOR) and (ii) cathode consisting of three different biocatalysts including GA, Lac, PEI and CNT for oxygen reduction reaction (ORR)[22]. We anticipate that our study will contribute to establish baseline protocols of mediatorless/membraneless EBC system
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
