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A Biofuel Cell with Electrochemically Switchable and Tunable Power Output

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Abstract:
An electroswitchable and tunable biofuel cell based on the biocatalyzed oxidation of glucose is
described. The anode consists of a Cu2+-poly(acrylic acid) film on which the redox-relay pyrroloquinoline
quinone (PQQ) and the flavin adenine dinucleotide (FAD) cofactor are covalently linked. Apo-glucose oxidase
is reconstituted on the FAD sites to yield the glucose oxidase (GOx)-functionalized electrode. The cathode
consists of a Cu2+-poly(acrylic acid) film that provides the functional interface for the covalent linkage of
cytochrome c (Cyt c) that is further linked to cytochrome oxidase (COx). Electrochemical reduction of the
Cu2+-poly(acrylic acid) films (applied potential -0.5 V vs SCE) associated with the anode and cathode
yields the conductive Cu0-poly(acrylic acid) matrixes that electrically contact the GOx-electrode and the
COx/Cyt c-electrode, respectively. The short-circuit current and open-circuit voltage of the biofuel cell
correspond to 105 íA (current density ca. 550 íA cm-2) and 120 mV, respectively, and the maximum
extracted power from the cell is 4.3 íW at an external loading resistance of 1 k¿. The electrochemical
oxidation of the polymer films associated with the electrodes (applied potential 0.5 V) yields the
nonconductive Cu2+-poly(acrylic acid) films that completely block the biofuel cell operation. By the cyclic
electrochemical reduction and oxidation of the polymer films associated with the anode and cathode between
the Cu0-poly(acrylic acid) and Cu2+-poly(acrylic acid) states, the biofuel cell performance is reversibly
switched between “ON” and “OFF” states, respectively. The electrochemical reduction of the Cu2+-polymer
film to the Cu0-polymer film is a slow process (ca. 1000 s) because the formation and aggregation of the
Cu0-clusters requires the migration of Cu2+ ions in the polymer film and their reduction at conductive sites.
The slow reduction of the Cu2+-polymer films allows for the controlling of the content of conductive domains
in the films and the tuning of the output power of the biofuel cell. The electron-transfer resistances of the
cathodic and anodic processes were characterized by impedance spectroscopy. Also, the overall resistances
of the biofuel cell generated by the time-dependent electrochemical reduction process were followed by
impedance spectroscopy and correlated with the internal resistances of the cell upon its operation.

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Informasi Detail

Judul Seri

J. AM. CHEM. SOC.

No. Panggil

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Penerbit

Washington, DC : American Chemical Society., 2003

Deskripsi Fisik

J. AM. CHEM. SOC. 2003, 125, 6803-6813

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

KIMIA

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

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