Ammonia synthesis using plasma-produced electrons

Patent metadata

Field	Value
Publication number	US-2019292063-A1
Application number	US-201916363548-A
Country	US
Kind code	A1
Filing date	Mar 25, 2019
Priority date	Mar 23, 2018
Publication date	Sep 26, 2019
Grant date	—

Abstract

A method of ammonia synthesis is described that includes contacting a nitrogen gas-containing plasma with an aqueous solution, thereby forming ammonia from the nitrogen gas and water. The nitrogen gas-containing plasma is present in an electrochemical cell. The electrochemical cell includes a container including an acidic liquid electrolyte. The electrochemical cell also includes a source of nitrogen gas, a metal electrode at least partially immersed in the electrolyte, a metal tube electrode spaced apart from a surface of the electrolyte by a predetermined spacing. The electrochemical cell is configured to provide a plasma spanning the predetermined space from the metal tube electrode to contact the surface of the electrolyte when power is applied to the metal tube electrode.

First claim

What is claimed is:

1 . A method of ammonia synthesis, comprising contacting a nitrogen gas-containing plasma with an aqueous solution, thereby forming ammonia from the nitrogen gas and water.

2 . The method of claim 1 , wherein the method is carried out at about 25 degree Celsius (° C.) and about 1 atmospheric pressure (atm).

3 . The method of claim 1 , wherein the aqueous solution has a pH of 5 or less.

4 . The method of claim 1 , wherein a current used to generate the nitrogen gas-containing plasma ranges from 1 mA to 8 mA.

5 . The method of claim 1 , wherein the nitrogen gas-containing plasma is a microplasma.

6 . The method of claim 1 , wherein the nitrogen gas-containing plasma is present in an electrochemical cell including a plasma-generating cathode and a metal anode.

7 . The method of claim 6 , wherein the metal anode is a platinum anode.

8 . The method of claim 6 , wherein the plasma-generating cathode comprises a stainless steel tube.

9 . The method of claim 6 , wherein the nitrogen gas is delivered to the aqueous solution from the plasma-generating cathode.

10 . The method of claim 9 , wherein the nitrogen gas is delivered at a flow rate of about 125 milliliter (mL) per minute.

11 . The method of claim 1 , wherein forming the ammonia from the nitrogen and water comprises forming the ammonia at an ammonia production rate of about 0.44 milligram per hour (mg/hour).

12 . The method of claim 1 , wherein forming the ammonia from the nitrogen and water is carried out at a faradaic efficiency of about 100%.

13 . An electrochemical cell for ammonia synthesis, comprising:
a container comprising an acidic liquid electrolyte; a source of nitrogen gas; a metal electrode at least partially immersed in the electrolyte; a metal tube electrode spaced apart from a surface of the electrolyte by a predetermined spacing; and wherein the electrochemical cell is configured to provide a plasma spanning the predetermined space from the metal tube electrode to contact the surface of the electrolyte when power is applied to the metal tube electrode.

14 . The electrochemical cell of claim 13 , wherein the source comprises a hollow conductive body including a first opening and a second opening comprising a nitrogen gas outlet and the second opening being separated from the surface of the acidic liquid electrolyte by the predetermined spacing.

15 . The electrochemical cell of claim 13 , wherein the metal electrode comprises a platinum electrode.

16 . The electrochemical cell of claim 13 , wherein the acidic liquid electrolyte has a pH of 5 or less.

17 . The electrochemical cell of claim 13 , wherein the source of nitrogen gas is configured to deliver the nitrogen gas at a flow rate of about 125 milliliter (mL) per minute.

18 . The electrochemical cell of claim 13 , wherein the metal tube electrode comprises a stainless electrode.

19 . The electrochemical cell of claim 13 , wherein the electrochemical cell has a volume of about 1 liters or less.

20 . The electrochemical cell of claim 13 , wherein the electrochemical cell has a volume of about 100 milliliter (mL) or less.

Assignees

• Univ Case Western Reserve

Inventors

• Renner Julie
• Sankaran R Mohan

Classifications

• C25B11/02

  characterised by shape or form · CPC title

• C25B15/08

  Supplying or removing reactants or electrolytes; Regeneration of electrolytes · CPC title

• C25B1/04

  by electrolysis of water · CPC title

• C01C1/0494 Primary

  using plasma or electric discharge · CPC title

• C25B15/02

  Process control or regulation · CPC title