# US 8,785,058 B2 · Integrated biofuel cell with aligned nanotube electrodes and method of use thereof

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- Number: US 8,785,058 B2
- Document ID: US8785058B2
- Status: Granted
- Kind: B2
- Application number: 11/784,085
- Filed: 2007-04-05
- Published: 2008-07-03
- Granted: 2014-07-22
- Earliest claimed: 2006-04-07
- Assignees: New Jersey Institute of Technology
- Applicants: Zafar Iqbal; Yubing Wang
- Inventors: Zafar Iqbal; Yubing Wang
- Web page: https://patentgrep.com/patent/US8785058B2

## CPC

- H01M 4/8803: {Supports for the deposition of the catalytic active composition (H01M4/90 takes precedence)}
- H01M 4/8647: {consisting of more than one material, e.g. consisting of composites}
- H01M 4/90: Selection of catalytic material
- H01M 4/9083: {on carbon or graphite}
- H01M 8/16: Biochemical fuel cells, i.e. cells in which microorganisms function as catalysts
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present disclosure provides for a method of forming, producing or manufacturing functionalized and soluble nanomaterials, most specifically carbon nanotubes on a substrate, which can be used in the production or manufacture of biofuel cells. One embodiment provides for the coupling of biofuel cells with a nanomaterial, wherein the nanomaterial supports catalytic enzymes. Another embodiment provides for a biofuel cell which uses enzymes immobilized on nanomaterials as electrodes. Another embodiment provides for the construction of a biofuel cell, wherein the application of a microwave process, and/or an electrochemical technique, is used to develop a biofuel cell having nanomaterial/enzyme-based electrodes on a substrate. Another embodiment provides for a composite of nanomaterial grown on a substrate, coupled to tethered or bonded enzymes, which makes it possible to fabricate direct electron transfer electrodes. A method for producing a nanomaterial-substrate system is also disclosed.

## Claims

### Claim 1

A biofuel cell system comprising:
an anode electrically coupled to a cathode; and
an electrolyte in electrical communication with the anode and the cathode;
wherein the anode includes a first microwave functionalized carbon nanomaterial on a first substrate, the first microwave functionalized carbon nanomaterial on the first substrate having at least one first enzyme directly immobilized by the first microwave functionalized carbon nanomaterial;
wherein the cathode includes a second microwave functionalized carbon nanomaterial on a second substrate, the second microwave functionalized carbon nanomaterial on the second substrate having at least one second enzyme directly immobilized by the second microwave functionalized carbon nanomaterial;
wherein the first microwave functionalized carbon nanomaterial enables direct electron transfer between the first substrate and the at least one first enzyme without a need for an additional electron transfer layer or electron-transfer mediator in the anode;
wherein the second microwave functionalized carbon nanomaterial enables direct electron transfer between the second substrate and the at least one second enzyme without a need for an additional electron transfer layer or electron-transfer mediator in the cathode;
wherein the at least one first enzyme is microwave bonded to the first microwave functionalized carbon nanomaterial thereby immobilizing the at least one first enzyme via direct covalent bonding interaction between the first microwave functionalized carbon nanomaterial and the at least one first enzyme; and
wherein the at least one second enzyme is microwave bonded to the second microwave functionalized carbon nanomaterial thereby immobilizing the at least one second enzyme via direct covalent bonding interaction between the second microwave functionalized carbon nanomaterial and the at least one second enzyme.

### Claim 2 (depends on 1)

The biofuel cell system of claim 1, wherein the at least one first enzyme includes glucose oxidase (GOx).

### Claim 3 (depends on 2)

The biofuel cell system of claim 2, wherein the electrolyte includes 100 mM β-D-glucose in pH 7 phosphate buffer.

### Claim 4 (depends on 1)

The biofuel cell system of claim 1, wherein the at least one second enzyme includes one of (i) bilirubin oxidase (BOD) and (ii) laccase.

### Claim 5 (depends on 1)

The biofuel cell system of claim 1, further comprising a porous polymer, and wherein the electrolyte is immobilized in the pores of the porous polymer.

### Claim 6 (depends on 5)

The biofuel cell system of claim 5, wherein the porous polymer is poly-tetrafluoroethylene (PTFE).

### Claim 7 (depends on 5)

The biofuel cell system of claim 5, wherein the biofuel cell system is utilized as an implanted device.

### Claim 8 (depends on 1)

The biofuel cell system of claim 1, further comprising a bio-compatible polymer, wherein the bio-compatible polymer encompasses the biofuel cell system.

### Claim 9 (depends on 8)

The biofuel cell system of claim 8, wherein the biofuel cell system is utilized as an implanted device.

### Claim 10 (depends on 1)

The biofuel cell system of claim 1, wherein at least one of the first and second carbon nanomaterial is selected from the group consisting of single wall carbon nanotubes (SWNTs), multiwall carbon nanotubes (MWNTs), carbon nanohorns, fullerenes, carbon nano onions, carbon nanocomposites and combinations thereof.

### Claim 11 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second substrates are silicon.

### Claim 12 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second substrates are porous silicon.

### Claim 13 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second substrates are polymeric substrates.

### Claim 14 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second substrates are carbon nanotube membranes.

### Claim 15 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second carbon nanomaterials are vertically oriented on the first and second substrates.

### Claim 16 (depends on 1)

The biofuel cell system of claim 1, wherein the first carbon nanomaterial includes a first plurality of carbon nanotubes, each carbon nanotube of the first plurality of carbon nanotubes having a fullerene C60 molecule chemically tethered thereto, and
wherein the second carbon nanomaterial includes a second plurality of carbon nanotubes, each carbon nanotube of the second plurality of carbon nanotubes having a fullerene C60 molecule chemically tethered thereto.

### Claim 17 (depends on 1)

The biofuel cell system of claim 1, wherein at least one micro-fluidic channel located on the first substrate suctionally communicates with the first microwave functionalized carbon nanomaterial; and
wherein at least one micro-fluidic channel located on the second substrate suctionally communicates with the second microwave functionalized carbon nanomaterial.

### Claim 18 (depends on 1)

The biofuel cell system of claim 1, wherein the first microwave functionalized carbon nanomaterials are a first plurality of fullerenes; and
wherein the second microwave functionalized carbon nanomaterials are a second plurality of fullerenes.

### Claim 19 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second microwave functionalized carbon nanomaterials are functionalized with carboxylic groups.

### Claim 20 (depends on 19)

The biofuel cell system of claim 19, wherein the at least one first enzyme is immobilized by covalent interaction between the carboxylic groups of the first microwave functionalized carbon nanomaterial and the at least one first enzyme; and
wherein the at least one second enzyme is immobilized by covalent interaction between the carboxylic groups of the second microwave functionalized carbon nanomaterial and the at least one second enzyme.

### Claim 21 (depends on 1)

The biofuel cell system of claim 1, wherein the at least one first enzyme is immobilized by covalent interaction between the first microwave functionalized carbon nanomaterial and amine groups on the at least one first enzyme; and
wherein the at least one second enzyme is immobilized by covalent interaction between the second microwave functionalized carbon nanomaterial and amine groups on the at least one second enzyme.

### Claim 22 (depends on 1)

The biofuel cell system of claim 1, wherein the at least one first enzyme is attached to ends of the first microwave functionalized carbon nanomaterial distal with respect to the first substrate; and
wherein the at least one second enzyme is attached to ends of the second microwave functionalized carbon nanomaterial distal with respect to the second substrate.

### Claim 23 (depends on 1)

The biofuel cell system of claim 1, wherein the first and second microwave functionalized carbon nanomaterials are functionalized with sulfonic groups.

### Claim 24 (depends on 23)

The biofuel cell system of claim 23, wherein the at least one first enzyme is immobilized by covalent interaction between the sulfonic groups of the first microwave functionalized carbon nanomaterial and the at least one first enzyme; and
wherein the at least one second enzyme is immobilized by covalent interaction between the sulfonic groups of the second microwave functionalized carbon nanomaterial and the at least one second enzyme.

### Claim 25

An electrode comprising:
a microwave functionalized carbon nanomaterial coupled directly to a substrate, and at least one enzyme directly immobilized by the microwave functionalized carbon nanomaterial;
wherein the microwave functionalized carbon nanomaterial enables direct electron transfer between the substrate and the at least one enzyme without a need for an additional electron transfer layer or electron-transfer mediator; and
wherein the at least one enzyme is microwave bonded to the microwave functionalized carbon nanomaterial thereby immobilizing the at least one enzyme via direct covalent bonding interaction between the microwave functionalized carbon nanomaterial and the at least one enzyme.

### Claim 26 (depends on 25)

The electrode of claim 25, wherein the at least one enzyme includes β-NAD (nicotinamide adenine dinucleotide) synthetase.

### Claim 27 (depends on 25)

The electrode of claim 25, wherein the carbon nanomaterial is selected from the group consisting of single wall carbon nanotubes (SWNTs), multiwall carbon nanotubes (MWNTs), carbon nanohorns, fullerenes, carbon nano onions, carbon nanocomposites and combinations thereof.

### Claim 28 (depends on 25)

The electrode of claim 25, wherein the electrode is included as a nanoelectrode in an electrochemical cell.

### Claim 29 (depends on 25)

The electrode of claim 25, wherein the electrode is included as a biosensor in a biofuel cell.

### Claim 30 (depends on 25)

The electrode of claim 25, wherein the substrate is silicon.

### Claim 31 (depends on 25)

The electrode of claim 25, wherein the substrate is porous silicon.

### Claim 32 (depends on 25)

The electrode of claim 25, wherein the substrate is polymeric substrates.

### Claim 33 (depends on 25)

The electrode of claim 25, wherein the substrate is carbon nanotube membranes.

### Claim 34 (depends on 25)

The electrode of claim 25, wherein the microwave functionalized carbon nanomaterial is vertically oriented on the substrate.

### Claim 35 (depends on 25)

The electrode of claim 25, wherein the microwave functionalized carbon nanomaterial includes a plurality of carbon nanotubes, each carbon nanotube of the plurality of carbon nanotubes having a fullerene C60 molecule chemically tethered thereto.

### Claim 36 (depends on 25)

The electrode of claim 25, wherein the microwave functionalized carbon nanomaterial is a plurality of fullerenes.

### Claim 37 (depends on 25)

The electrode of claim 25, wherein at least one micro-fluidic channel is located on the substrate, wherein the at least one micro-fluidic channel suctionally communicates with the microwave functionalized carbon nanomaterial.

### Claim 38 (depends on 25)

The electrode of claim 25, wherein the microwave functionalized carbon nanomaterial is functionalized with carboxylic groups.

### Claim 39 (depends on 38)

The electrode of claim 38, wherein the at least one enzyme is immobilized by covalent interaction between the carboxylic groups of the microwave functionalized carbon nanomaterial and the at least one enzyme.

### Claim 40 (depends on 25)

The electrode of claim 25, wherein the at least one enzyme is immobilized by covalent interaction between the microwave functionalized carbon nanomaterial and amine groups on the at least one enzyme.

### Claim 41 (depends on 25)

The electrode of claim 25, wherein the at least one enzyme is attached to ends of the microwave functionalized carbon nanomaterial distal with respect to the substrate.

### Claim 42 (depends on 25)

The electrode of claim 25, wherein the microwave functionalized carbon nanomaterial is functionalized with sulfonic groups.

### Claim 43 (depends on 42)

The electrode of claim 42, wherein the at least one enzyme is immobilized by covalent interaction between the sulfonic groups of the microwave functionalized carbon nanomaterial and the at least one enzyme.

### Claim 44 (depends on 25)

A method for producing the electrode of claim 25, the method comprising:
coupling the carbon nanomaterial directly to the substrate via a chemical vapor deposition (“CVD”) process; and
bonding the at least one enzyme directly to the carbon nanomaterial thereby immobilizing the at least one enzyme.

### Claim 45 (depends on 44)

The method of claim 44, wherein the CVD process includes utilizing a catalyst deposition step to deposit a catalyst/promoter precursor on the substrate, wherein the catalyst/promoter precursor is deposited on the substrate utilizing at least one of: (i) a dip coating technique and (ii) a spin coating technique.

### Claim 46 (depends on 44)

The method of claim 44, wherein the CVD process includes ethanol chemical vapor deposition.

### Claim 47 (depends on 25)

A method for utilizing the electrode of claim 25, the method comprising adapting the electrode for use as a biosensor and utilizing the electrode to detect an analyte.

### Claim 48 (depends on 47)

The method of claim 47, wherein the electrode is adapted for use as a biosensor in a biofuel cell, wherein the analyte is a chemical constituent of the biofuel cell.

### Claim 49 (depends on 47)

The method of claim 47, wherein the at least one enzyme includes glucose oxidase (GOx), and wherein the analyte is glucose.