2.7 Electrode Materials
49
2.7 Electrode Materials
Various materials including carbon, metals, and semiconductors can be utilized as
platforms for MET-type bioelectrocatalysis. Although rapid electron transfer have
been found between redox mediators and several planar electrodes such as glassy
carbon (GC), Au disk and indium–tin-oxide (ITO), materials with lager specific
surface area (in a precise sense, with large values for surface-to-weight ratio) have
been proposed to improve the performance of MET-type bioelectrocatalysis because
of the increased amounts of enzymes and mediators. Carbon clothes, carbon papers,
and carbon felts, which are made with carbon fibers of different diameters, are usually
utilized for MET-type reaction. Barton et al. were the first to report the use of a carbon
cloth modified with Os polymers and laccase from Rhus vernicifera and Coriolus
hirsutus [75, 76]. They attained a current density of 5 mA cm
−2 at 0.57 V vs Ag|AgCl
in a pH 5 chloride-free citrate buffer at 37.5 °C. In this pioneering work, the authors
demonstrated that a 50-fold increase in surface area lead to a multiplication of the
O 2 reduction current by a factor of 5.
On the other hand, nanostructured material-based electrodes with porous surface
were also often employed to furthermore improve the performance of MET-type
bioelectrocatalysis. Tsujimura et al. reported high performance of MET-type bioelectrodes for both glucose oxidation [49] and O 2 reduction [77] by using magnesium
oxide-templated mesoporous carbon electrode (MgOCE). A high limiting current
density of 145 mA cm
−2 was recorded for HCOO
− oxidation at FoDH modified
Ketjen Black-modified electrodes (KBEs), by using methyl viologen (MV) as a free
mediator [78]. An O 2 reduction current density of 27 mA cm
−2 was realized at
neutral pH by co-immobilizing BOD and 2,2
-azinobis(3-ethylbenzothiazoline-6sulfonate (ABTS) at a hollow CNTs modified carbon clothes gas-diffusion electrode
[79]. The improved performance of MET-type bioelectrocatalysis could be explained
by increased enzyme immobilization, effective electron and mass transfer at such
microstructured electrodes.
In addition, functionalized materials have also been developed for MET-type
bioelectroatalysis. For an example, glassy carbon electrochemically grafted a mediator illustrated a good performance for MET-type bioelectrocatalysis of PQQdependant GDH [80]. Yamaguchi et al. also reported hydroquinone functionalized
carbon black for bioelectrocatalysis of GOD [81].
References
1. Delahay P (1980) New instrumental methods in electrochemistry. Chap. 5. Robert E. Krieger
Publishing Company, New York
2. Kitazumi Y, Kano K (2015) Electrode reactions using redox enzymes and microbes.
Electrochemistry 83:1079–1084 ([In Japanese])
3. Matsumoto R, Kano K, Ikeda T (2002) Theory of steady-state catalytic current of mediated
bioelectrocatalysis. J Electroanal Chem 535:37–40
49
2.7 Electrode Materials
Various materials including carbon, metals, and semiconductors can be utilized as
platforms for MET-type bioelectrocatalysis. Although rapid electron transfer have
been found between redox mediators and several planar electrodes such as glassy
carbon (GC), Au disk and indium–tin-oxide (ITO), materials with lager specific
surface area (in a precise sense, with large values for surface-to-weight ratio) have
been proposed to improve the performance of MET-type bioelectrocatalysis because
of the increased amounts of enzymes and mediators. Carbon clothes, carbon papers,
and carbon felts, which are made with carbon fibers of different diameters, are usually
utilized for MET-type reaction. Barton et al. were the first to report the use of a carbon
cloth modified with Os polymers and laccase from Rhus vernicifera and Coriolus
hirsutus [75, 76]. They attained a current density of 5 mA cm
−2 at 0.57 V vs Ag|AgCl
in a pH 5 chloride-free citrate buffer at 37.5 °C. In this pioneering work, the authors
demonstrated that a 50-fold increase in surface area lead to a multiplication of the
O 2 reduction current by a factor of 5.
On the other hand, nanostructured material-based electrodes with porous surface
were also often employed to furthermore improve the performance of MET-type
bioelectrocatalysis. Tsujimura et al. reported high performance of MET-type bioelectrodes for both glucose oxidation [49] and O 2 reduction [77] by using magnesium
oxide-templated mesoporous carbon electrode (MgOCE). A high limiting current
density of 145 mA cm
−2 was recorded for HCOO
− oxidation at FoDH modified
Ketjen Black-modified electrodes (KBEs), by using methyl viologen (MV) as a free
mediator [78]. An O 2 reduction current density of 27 mA cm
−2 was realized at
neutral pH by co-immobilizing BOD and 2,2
-azinobis(3-ethylbenzothiazoline-6sulfonate (ABTS) at a hollow CNTs modified carbon clothes gas-diffusion electrode
[79]. The improved performance of MET-type bioelectrocatalysis could be explained
by increased enzyme immobilization, effective electron and mass transfer at such
microstructured electrodes.
In addition, functionalized materials have also been developed for MET-type
bioelectroatalysis. For an example, glassy carbon electrochemically grafted a mediator illustrated a good performance for MET-type bioelectrocatalysis of PQQdependant GDH [80]. Yamaguchi et al. also reported hydroquinone functionalized
carbon black for bioelectrocatalysis of GOD [81].
References
1. Delahay P (1980) New instrumental methods in electrochemistry. Chap. 5. Robert E. Krieger
Publishing Company, New York
2. Kitazumi Y, Kano K (2015) Electrode reactions using redox enzymes and microbes.
Electrochemistry 83:1079–1084 ([In Japanese])
3. Matsumoto R, Kano K, Ikeda T (2002) Theory of steady-state catalytic current of mediated
bioelectrocatalysis. J Electroanal Chem 535:37–40