Thermal Annealing‐Enhanced Bioelectrocatalysis in Membraneless Glucose/Oxygen Biofuel Cell based on Hydrophilic Carbon Fibers

Abstract

AbstractThe electrode material is a pivotal component in achieving efficient electron transfer in an enzymatic biofuel cell (EBFC). Herein, novel hydrophilic carbon fibers (HCFs) with a helical structure are synthesized through chemical vapor deposition and are used as an electrode material for the immobilization of biocatalysts to fabricate bioelectrodes, where glucose dehydrogenase, serving as the anodic enzyme, is co‐immobilized with 1,4‐naphthoquinone on the HCFs for the catalysis of the glucose oxidation reaction (GOR), and bilirubin oxidase, as the cathodic enzyme, is co‐immobilized with protoporphyrin IX for the catalysis of the oxygen reduction reaction (ORR). It is found that thermal annealing the HCFs improves the bioelectrocatalytic performances of the as‐fabricated bioanode for the GOR and biocathode for the ORR, owing to the enhanced electron transfer kinetics. Subsequently, a membraneless glucose/O2 EBFC assembled by using the as‐synthesized bioelectrodes is able to generate a high open circuit voltage of 0.8 V and a maximum power density of 0.7 mW cm−2 at 0.44 V with good operational stability. The practicability in fabricating membraneless EBFCs makes the synthesized HCFs promising in miniature bioenergy devices.