Carbon‐Nanotube‐Based Glucose/O₂ Biofuel Cells

Abstract

Biofuel cells (BFCs) utilize biocatalysts such as enzymes and microorganisms for the conversion of chemical energy into electrical energy. [1][2][3][4] These BFCs represent a new kind of energy-conversion technology that is distinct from conventional fuel cells, such as H 2 /O 2 and methanol/O 2 fuel cells, mainly in that they can operate under moderate conditions, such as in mild media and at ambient temperatures. Moreover, compared with the noble-metal catalysts used in conventional fuel cells, the biocatalysts used in the BFCs are more efficient and selective toward the biomass. More remarkably, the biomass consumed by the BFCs, such as glucose and oxygen, is generally endogenous to biological systems. As such, BFCs are envisaged to be able to power the bioelectronics in vivo, finding uses in systems such as implantable biosensors or pacemakers in the human body. [5][6][7][8] These striking properties and the potential applications of BFCs have evoked intensive interest in the basic study and development of BFCs in recent years. [9][10][11][12][13][14] It is known that carbon nanotubes (CNTs), a new kind of carbon-based nanomaterial, possess unique structural and electronic properties, and are finding striking applications in various research and industrial fields, [15][16][17][18][19][20][21] including electrochemistry. [22][23][24] In addition to their excellent electrochemical properties, CNTs have several characteristics that make them very suitable for the development of enzymatic BFCs. For example, CNTs bear graphene sidewalls that are chemically inert and highly hydrophobic, with a dense p-p stacking. Such a property essentially makes CNTs well suited as a support for the redox mediators [25][26][27] generally employed for shuttling the electron transfer of biocatalysts, for example enzymes and proteins, or for the conversion and oxidation of the NADH (nicotinamide adenine dinucleotide with hydrogen) cofactor when dehydrogenases are used as the anode biocatalysts. Moreover, as demonstrated recently, [28][29][30] the use of CNTs could largely facilitate the direct electron transfer of the enzymes and proteins. On the other hand, CNTs have a good conductivity (depending on the sort of CNTs used) and a high surface area to weight ratio (ca. 300 m 2 g -1 ) [31] as well as the ability to form a 3D matrix that can be used for both enzyme immobilization and electrode reactions.In this Communication we demonstrate the first singlewalled carbon nanotube (SWNT)-based glucose/O 2 biofuel cell with glucose dehydrogenase (GDH) as the anode biocatalyst for the oxidation of glucose, with NAD + as the cofactor and laccase (from Trametes versicolor) as the cathode biocatalyst for O 2 reduction (Scheme 1). On the SWNT anode, methylene blue (MB) was adsorbed through the interactions between MB and SWNTs, as described in our earlier work.[25]Although the formed MB-SWNT adsorptive adduct exhibits excellent electrochemical properties and a good stability, its activity for redox-mediating the oxidation of NADH was found to be...

Layer-by-Layer Assembly of Carbon Nanotubes Modified with Invertase/Glucose Dehydrogenase Cascade for Sucrose/O2Biofuel Cell

“…[39][40][41] Characteristic voltammograms for 1 mM NADH mediation on GCEs and SPEs were shown in Fig. 2.…”

An Ethanol/O2 Biofuel Cell Based on an Electropolymerized Bilirubin Oxidase/Pt Nanoparticle Bioelectrocatalytic O2‐Reduction Cathode

“…Recently, carbon nanotubes (CNTs) were implemented as an active material for direct electrical contact between laccase or BOD and electrodes, and cathodes allowing the four-electron bioelectrocatalyzed reduction of O 2 to H 2 O were prepared. [12,13] Also, in a recent study, [14] CNTs were used as an active matrix for the fabrication of a biofuel cell anode and cathode elements. The anodes in these systems consisted of NAD þ -dependent enzymes (glucose dehydrogenase or alcohol dehydrogenase) that were reconstituted on a relay-NAD þ monolayer associated with the CNTs.…”

Rational Functionalization of Carbon Nanotubes Leading to Electrochemical Devices with Striking Applications

“…The striking properties and potential applications of BFCs have triggered intense interest both in basic studies and in the practical development of BFCs in recent years. [17] In an earlier attempt, [18] we developed a CNT bioanode for the oxidation of glucose by adsorption of methylene blue (MB) monomer onto CNTs by means of p-stacking interaction between the two components. The MB monomer was further subjected to electropolymerization to form a polymeric film on the CNTs, which exhibited improved electrocatalytic activity for the oxidation of NADH.…”