Hydrogen gas generation utilizing a bromide electrolyte and radiant energy

• US 4,203,814 A
• Filed: 11/01/1978
• Issued: 05/20/1980
• Est. Priority Date: 11/01/1978
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Grantham, Daniel H.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US05/956,760
• Time in Patent Office: 566 Days
• Field of Search: 204/128, 204/129, 204/DIG. 3, 429/111
• US Class Current: 205/340
• CPC Class Codes: C25B 1/02 Hydrogen or oxygen
• CPC Class Codes: C25B 1/04 by electrolysis of water
• CPC Class Codes: C25B 1/24 Halogens or compounds thereof
• CPC Class Codes: C25B 1/55 Photoelectrolysis
• CPC Class Codes: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y10S 204/03 Auxiliary internally generated electrical energy

Abstract

Radiant energy to at least partially power an electrolytic cell is used in the generation of hydrogen, utilizing a bromide, preferably hydrogen bromide, as the essential electrolyte component in the electrolytic cell to solve overvoltage and corrosion problems associated with the use of conventional electrolytes in similar environments. The use of such material also results in a broadening of the selection of semiconductor electrodes which can be used in such process and apparatus. The semiconductors employed are generally nonmetals and can be multilayered structures comprised of a gradient of diminishing width band gap material. The hydrogen generated from such system can be used to power a fuel cell.

Claims

1. A process for producing hydrogen gas from an electrolyte solution in an electrolytic cell, wherein the improvement comprises utilizing a solution of a bromide compound as the electrolyte in conjunction with radiant energy and a semiconducting silicon electrode to at least partially power the electrolytic cell.

5. The process of claims 1, 2 or 4 wherein the bromide electrolyte is selected from the group consisting of HBr, NaBr, KBr, LiBr, CsBr, SrBr₂ and mixtures thereof.

6. The process of claim 5 wherein the bromide compound is present in an amount of up to about 50% by weight and the solvent is water.

7. The process of claims 1, 2, 3 or 4 wherein the radiant energy is solar energy.

8. The process of claims 1, 2, 3 or 4 wherein the radiant energy is laser radiation.

9. The process of claims 1, 2, 3 or 4 wherein the radiant energy is produced by a light emitting solid state diode.

10. The process of claims 1, 2, 3 or 4 wherein the radiant energy is light of wavelength up to 11,000 A.

11. The process of claims 1, 2, 3 or 4 wherein the electrolyte is a 48% by weight solution of HBr in water.

12. The process of claims 1, 2, 3 or 4 wherein at least part of the energy necessary to power the cell is provided by an external power source comprising a battery.

2. The process of producing hydrogen gas in an electrolytic cell comprising:

providing an electrolytic cell enclosure containing a bromide electrolyte solution;

immersing an n-type semiconducting silicon anode and a p-type semiconducting silicon cathode into the bromide electrolyte solution;

separating said electrodes by a hydrogen ion permeable membrane also immersed in said bromide electrolyte solution;

exposing the semiconducting electrodes to radiant energy of proper wavelength and sufficient intensity to cause the evolution of hydrogen gas at the cathode and bromine liquid at the anode.

3. A process of producing hydrogen gas in an electrolytic cell comprising:

providing an electrolytic cell enclosure containing a hydrogen bromide electrolyte solution;

placing a platinum electrode and a semiconducting silicon electrode into the hydrogen bromide electrolyte solution, wherein the semiconducting electrode also forms part of the wall of the electrolytic cell enclosure containing the platinum electrode and hydrogen bromide solution;

irradiating the semiconducting electrode from that side of the semiconducting electrode which represents the wall portion of the cell containing the hydrogen bromide solution with radiant energy of proper wavelength and sufficient intensity to result in the evolution of hydrogen gas at the platinum electrode and liquid bromine at the semiconducting electrode.

4. The process of producing hydrogen gas in an electrolytic cell comprising:

providing an electrolytic cell enclosure containing a bromide electrolyte solution;

placing a platinum electrode and a semiconducting silicon electrode in the bromide electrolyte solution;

subjecting the semiconductor electrode to a radiant energy source of proper wavelength and sufficient intensity to evolve hydrogen gas from the platinum electrode in the space between the two electrodes and liquid bromine into the solution between the area defined by the electrodes.