Photoelectrochemical device containing a quantum confined group IV semiconductor nanoparticle

• US 6,361,660 B1
• Filed: 05/08/2000
• Issued: 03/26/2002
• Est. Priority Date: 07/31/1997
• Status: Expired due to Term

• Current Assignee: Avery N. Goldstein
• Original Assignee: Avery N. Goldstein
• Inventors: Goldstein, Avery N.
• Primary Examiner(s): Wong, Edna
• Application Number:
  US09/567,109
• Time in Patent Office: 687 Days
• Field of Search: 204/157.4, 204/157.15, 204/157.52, 204/157.5, 204/157.6
• US Class Current: 204/157.15
• CPC Class Codes: B01D 53/885 Devices in general for catalytic purification of waste gases
• CPC Class Codes: B01J 19/122 Incoherent waves gamma-radiation B01J19/082
• CPC Class Codes: C01B 13/0207 Water
• CPC Class Codes: C01B 17/66 Dithionites or hydrosulfites (S2O42-)
• CPC Class Codes: C01B 3/042 Decomposition of water
• CPC Class Codes: C01B 3/26 using catalysts
• CPC Class Codes: C01D 5/00 Sulfates or sulfites of sodium, potassium or alkali metals in general sulfites in general C01B17/62
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight

Abstract

A process for reacting a molecule using light as an energy source is described which comprises exposing the molecule to a catalyst material, the catalyst material in contact with an illuminated, quantum confined Group IV semiconductor domain of silicon or germanium. The Group IV semiconductor domain having a band gap greater than bulk silicon and sufficiently large for reacting the molecule. The process is particularly useful in decomposing water into hydrogen and oxygen, as well as photocatalytically degrading pollutants in a waste stream. A device based on a Group IV semiconductor nanoparticles for conducting photo electrochemistry is also disclosed.

Claims

1. A photolytic process for the reaction of a molecule comprising the steps of:

exposing a Group IV semiconductor domain possessing a quantum confined energy band gap, greater than that of a bulk of said Group IV semiconductor domain and having a size between 1 and 50 nanometers, the surface of said domain in electrical contact with at least one catalytic material to photons of an energy equal to or greater than the energy band gap of said Group IV semiconductor domain, and greater than the energy sufficient for the reaction of said molecule; and

placing said molecule in contact with said catalytic material.

2. The process of claim 1 wherein said photons are solar radiation.

3. The process of claim 1 wherein said photons are artificial radiation.

4. The process of claim 1 wherein said molecule is water.

5. The process of claim 1 wherein said molecule is an aqueous organic compound.

6. The process of claim 1 further comprising the step of:

affixing said Group IV semiconductor domain to a substrate.

7. The process of claim 6 further comprising the step of:

providing a container for said domain and said substrate such that a stream containing said molecule flows over and in contact with said domain.

8. The process of claim 1 further comprising the step of:

passivating said Group IV semiconductor domain.

9. The process of claim 8, wherein passivating is accomplished by a technique selected from the group consisting of:

growing a silicon oxide film on the surface of said domain of a formula SiO_n, where n is between one and two, inclusive;

adhering an organosilicon compound to said Group IV semiconductor surface having a functionality reactive toward said Group IV semiconductor domain and adhering an organic compound having a functionality reactive toward said Group IV semiconductor domain.

10. A photolytic process for the reaction of a molecule comprising the steps of:

exposing a Group IV semiconductor domain possessing a quantum confined energy band gap, greater than that of a bulk of said Group IV semiconductor domain and having a size between 1 and 50 nanometers, the surface of said domain in electrical contact with at least one catalytic material to photons of an energy equal to or greater than the energy band gap of said Group IV semiconductor domain, and greater than the energy sufficient for the reaction of said molecule;

placing said molecule in contact with said catalytic material; and

derivatizing said catalytic material with a receptor molecule.

11. The process of claim 10 wherein the receptor molecule is selected from the group consisting of:

an antibody variable chain region;

peptide sequences;

enzymes;

electrically conducting polymers;

mono—

and bi-layers of organic molecules, having a molecular weight of less than 1000.