In situ growth of hybrid nanoflowers on activated carbon fibers as electrodes for mediatorless enzymatic biofuel cells

Abstract

Hybrid nanoflowers (HnFs) are novel structures that comprise enzymes (laccase, glucose oxidase, or catalase) and Cu3(PO4)2-based crystals, which can directly in situ grow on activated carbon fibers (ACFs) for the preparation of electrodes (HnF/ACF) used in glucose biofuel cells. The HnF/ACF structures perform higher enzymatic activities (~4 times) and stability (~2 times) than the enzymes physically adsorbed on ACFs in distinct analyses such as epinephrine oxidation, H2O2 decomposition, and glucose oxidation. The power density of an HnF/ACF-based cell (50 µW cm−2 for a glucose concentration of 50 mM) is 3–5 times higher than that of a cell prepared from conventional enzyme immobilization routes, which can be sustained at up to 80% after one month of operation.