EP4339326A1 - Paired electrosynthesis process for (co)production hydroxylamine and ammonia - Google Patents

Paired electrosynthesis process for (co)production hydroxylamine and ammonia Download PDF

Info

Publication number
EP4339326A1
EP4339326A1 EP22195550.3A EP22195550A EP4339326A1 EP 4339326 A1 EP4339326 A1 EP 4339326A1 EP 22195550 A EP22195550 A EP 22195550A EP 4339326 A1 EP4339326 A1 EP 4339326A1
Authority
EP
European Patent Office
Prior art keywords
compartment
electrolyte
based catalysts
anode
cathode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22195550.3A
Other languages
German (de)
French (fr)
Inventor
Jan Vaes
Yuvray Y. BIRDJA
Jason SONG
Metin BULUT
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vito NV
Original Assignee
Vito NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vito NV filed Critical Vito NV
Priority to EP22195550.3A priority Critical patent/EP4339326A1/en
Priority to PCT/EP2023/075120 priority patent/WO2024056718A2/en
Publication of EP4339326A1 publication Critical patent/EP4339326A1/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/27—Ammonia
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • C25B11/032—Gas diffusion electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/13—Single electrolytic cells with circulation of an electrolyte
    • C25B9/15—Flow-through cells
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms

Definitions

  • the present invention is directed to a paired electrosynthesis process for the (co)production of hydroxylamine (HA) and/or ammonia out of N 2 or air and water. It further provides an electrolyzer developed for said purpose comprising both a porous cathode and anode with an effective catalyst layer and based on a continuous flow process.
  • the process and electrolyzer of the present invention are particularly useful to efficiently convert reactants such as NO 3 -, NO 2 -, NO x and N 2 at both, the cathode and anode.
  • the electrosynthesis of nitrogen species such as ammonia and HA are promising in view of renewable energy storage and electrification of the chemical industry.
  • the current production of ammonia leads to large CO 2 emissions due to the fossil fuel based Haber Bosch process.
  • Electrochemical reduction of dinitrogen/NO 3 - is a sustainable process for ammonia synthesis without CO 2 emissions when renewable electricity is used.
  • the production of HA is important for the production of caprolactam, a precursor of nylon-6.
  • waste water streams can be utilized since they contain nitrates and nitrites.
  • the present invention provides an electrochemical flow reactor configured for paired electrosynthesis of NH 3 and/or Hydroxylamine (HA), said reactor comprising metal electrocatalyst based porous gas diffusion electrodes (GDEs) as cathode and anode.
  • GDEs metal electrocatalyst based porous gas diffusion electrodes
  • the electrochemical flow cell reactor is characterized in that the metal electrocatalysts are selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  • the metal electrocatalysts of the cathode and the metal electrocatalysts of the anode are different.
  • the metal electrocatalysts of the cathode are selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  • the metal electrocatalysts of the cathode is selected from a Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, Nickel, and Palladium; more in particular the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, and Nickel,
  • the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, Palladium, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy; more in particular the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy.
  • the electrochemical flow cell reactor will typically comprise an anode and a cathode compartment separated by an ion exchange membrane or a one-compartment system where the cathode and anode are not separated from each other.
  • the person skilled in the art is aware of the ion exchange membrane separators used in electrochemical flow cell reactors, including cation exchange membranes, anion exchange membranes and bipolar membranes.
  • said anode and cathode compartment each preferably comprise an electrolyte compartment and a gas compartment separated from one another by means of the metal electrocatalyst based porous GDEs, configured for gas from the gas compartment to reach the metal electrocatalyst from the GDEs, wherein the metal electrocatalyst is configured to be in contact with the electrolyte from the electrolyte compartment.
  • the electrolyte compartment of the anode compartment and the electrolyte compartment of the cathode compartment comprise a common electrolyte (either an alkaline or acidic electrolyte; in particular alkaline), wherein the outlet of the electrolyte compartment of the anode compartment is fluidly connected to the inlet of the electrolyte compartment of the cathode compartment.
  • a common electrolyte either an alkaline or acidic electrolyte; in particular alkaline
  • the gas compartment of the anode compartment and the gas compartment of the cathode compartment comprise a gas inlet for a Nitrogen containing gas (such as N 2 , NO, NO 2 , N 2 O and mixtures thereof), in particular dinitrogen (N 2 ) gas.
  • a Nitrogen containing gas such as N 2 , NO, NO 2 , N 2 O and mixtures thereof
  • N 2 dinitrogen
  • the present invention provides an electrochemical flow cell reactor for paired electrosynthesis of NH 3 and/or Hydroxylamine (HA) from a Nitrogen containing gas, wherein the dinitrogen (N 2 ) from the Nitrogen containing gas from a gas compartment of the anode compartment is oxidized at the anode with the formation of NOx, Nitrate (NO 3 - ) and/or Nitrite (NO 2 - ) in the electrolyte of the anode compartment, wherein the thus obtained Nitrate (NO 3 - ) containing electrolyte is fed into to electrolyte compartment of the cathode compartment, to be reduced at the cathode together with the Nitrogen (N 2 ) from the Nitrogen containing gas from the gas compartment of the cathode compartment with the formation of Ammonia (NH 3 ) and/or hydroxylamine (HA) in the electrolyte of the cathode compartment, and removing the thus obtained Ammonia (NH 3 ) and/or hydroxy
  • the electrochemical flow cell reactor further comprising a separator to retrieve the Ammonia (NH 3 ) and/or hydroxylamine (HA) from the Ammonia (NH 3 ) and/or hydroxylamine (HA) containing electrolyte, and recycling the electrolyte into the electrolyte compartment of the anode compartment.
  • a separator to retrieve the Ammonia (NH 3 ) and/or hydroxylamine (HA) from the Ammonia (NH 3 ) and/or hydroxylamine (HA) containing electrolyte, and recycling the electrolyte into the electrolyte compartment of the anode compartment.
  • the present invention provides a method of paired electrosynthesis of NH 3 and/or Hydroxylamine (HA) in an electrochemical flow cell reactor comprising an anode and a cathode compartment separated by an ion exchange membrane, said method comprising;
  • the method of paired electrosynthesis of NH 3 and/or Hydroxylamine (HA) is characterized in that the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and wherein the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  • Figure 1 herein also referred to as Fig. 1 , provides a schematic diagram of the paired electrosynthesis process for NH 3 / HA production.
  • the present invention is in particular directed to a paired electrosynthesis process for the (co)production of hydroxylamine (HA) and/or ammonia out of N 2 or air and water. It provides thereto a continuous flow process and a continuous electrochemical flow reactor with porous electrodes at both the anode and the cathode, wherein each of said porous electrodes comprise a metal electrocatalyst layer.
  • such continuous electrochemical flow reactor consists of a membrane or diaphragm, separating the anode and the cathode compartment and at either side a metal electrocatalyst layer incorporated in a gas diffusion electrode (GDE) to enhance mass transport and increase the electrochemical active surface area.
  • GDE gas diffusion electrode
  • Nitrate (NO 3 - ) source is hard to get (waste water can be used, however, the concentration of nitrates and nitrites herein are typically too low to produce large amounts of ammonia and / or HA) the technical realization of an electrochemical process for HA and/or ammonia synthesis has thus far been hindered by;
  • the invention also benefits from a synergistic effect by co-reduction of N 2 and NO 3 - or NO 2 - at the cathode which can be controlled by the potential window. Compared to the existing technologies, this results in high product yields of HA and/or ammonia.
  • the present invention utilizes the anode reaction products in a paired electrosynthesis concept for the production of HA and ammonia.
  • electrodes reported for NRR to ammonia there are no indications in the literature to co-produce with 100% selectivity only ammonia or HA.
  • Nitrogen oxidation has not been carried out electrochemically in a continuous flow cell which is the key of our anode reaction. It is accordingly an object of the present invention to provide the use of Nitrogen oxidation, i.e.
  • Electrochemical Nitrogen Oxidation Reaction in the electrochemical synthesis of ammonia and/or hydroxylamine, more in particular the use of NOR in a continuous flow cell configuration, in the electrochemical synthesis of ammonia and/or hydroxylamine.
  • the present invention accordingly provides for the use of the products obtained from the anodic oxidation of Nitrogen as reactant for a cathodic reaction to produce NH 3 and/or HA.
  • the present invention accordingly provides for the use of the products obtained from the anodic oxidation of Nitrogen in a continuous flow cell, as reactant for a cathodic reaction to produce NH 3 and/or HA, more in particular as reactant for a cathodic reaction to produce NH 3 and/or HA in a continuous flow cell.
  • Fig. 1 provides a schematic diagram for the paired electrosynthesis of ammonia and/or HA in a continuous electrochemical flow cell reactor (1) using the anodic reaction products as reactant for the cathodic reduction.
  • the electrochemical flow cell reactor comprises an anode compartment (2) and a cathode compartment (3) separated from one another by an ion exchange membrane (4).
  • Both the anode compartment and the cathode compartment are configured as a continuous flow cell, and accordingly comprise an electrolyte compartment (5, 6) comprising a common electrolyte (20) (in the present example an alkaline electrolyte) and a gas compartment (7, 8) separated from one another by means of a metal electrocatalyst based porous GDE (9, 10).
  • the GDE of the anode compartment (9) is configured for N 2 containing gas (13) from the gas compartment (7) to reach the metal electrocatalyst layer (11) of the anode which is in contact with the alkaline electrolyte (20) of the anode electrolyte compartment (5).
  • Nitrogen is oxidized with the formation of Nitrate (NO 3 - )/Nitrite (NO 2 - ) in the alkaline electrolyte.
  • Nitrate (NO 3 - ) containing alkaline electrolyte (21) is fed by means of a fluid connection (19) into the electrolyte compartment of the cathode cell (6).
  • another GDE (10) is present and configured for N 2 containing gas (14) from the gas compartment (8) the reach the metal electrocatalyst layer (12) of the cathode which is in contact with the Nitrate (NO 3 - ) containing alkaline electrolyte (21) of the cathode electrolyte compartment (6).
  • the double arrow symbolises a separator to separate Ammonia (NH 3 ) and/or Hydroxylamine (HA) from the Ammonia (NH 3 ) and/or Hydroxylamine (HA) containing alkaline electrolyte (22), with possible recycling of the alkaline electrolyte (20) into the electrolyte compartment of the anode (5).
  • the recycling of the alkaline electrolyte (20) is an optional step in the method as disclosed.
  • the separator as used is simply to indicate any possible means and procedures to obtain the reaction products Ammonia (NH 3 ) and/or Hydroxylamine (HA), from the Ammonia (NH 3 ) and/or Hydroxylamine (HA) containing alkaline electrolyte (22).
  • the alkaline electrolyte is an aqueous alkaline electrolyte
  • the electrochemical flow cell reactor may also act as an electrolyzer with the formation of Oxygen (O 2 ) gas at the anode and Hydrogen (H 2 ) gas at the cathode.
  • O 2 Oxygen
  • H 2 Hydrogen

Abstract

The present invention is directed to a paired electrosynthesis process for the (co)production of hydroxylamine (HA) and/or ammonia out of N2 or air and water. It further provides an electrolyzer developed for said purpose comprising both a porous cathode and anode with an effective catalyst layer and based on a continuous flow process. The process and electrolyzer of the present invention are particularly useful to efficiently convert reactants such as NO3 -, NO2 -, NOx and N2 at both, the cathode and anode.

Description

    FIELD OF THE INVENTION
  • The present invention is directed to a paired electrosynthesis process for the (co)production of hydroxylamine (HA) and/or ammonia out of N2 or air and water. It further provides an electrolyzer developed for said purpose comprising both a porous cathode and anode with an effective catalyst layer and based on a continuous flow process. The process and electrolyzer of the present invention are particularly useful to efficiently convert reactants such as NO3-, NO2-, NOx and N2 at both, the cathode and anode.
    • BACKGROUND TO THE INVENTION
  • The electrosynthesis of nitrogen species such as ammonia and HA are promising in view of renewable energy storage and electrification of the chemical industry. In particular, the current production of ammonia leads to large CO2 emissions due to the fossil fuel based Haber Bosch process. Electrochemical reduction of dinitrogen/NO3 - is a sustainable process for ammonia synthesis without CO2 emissions when renewable electricity is used. Moreover, the production of HA is important for the production of caprolactam, a precursor of nylon-6. For the electrochemical production of ammonia and/or HA, also waste water streams can be utilized since they contain nitrates and nitrites.
  • However, the current technology for an Electrochemical Nitrogen Reduction Reaction (NRR) is facing a poor product selectivity leading to very little amounts of NH3 or HA products to be formed. Moreover, the reliability of many experiments in the field are questioned due to the little amounts of products produced, which cannot be accurately ascribed to the conversion of N2 or NO3 - or NO2 -. Also the current Electrochemical Nitrate Reduction Reaction (NO3RR) for HA formation is still only realized at lab scale, using batch type of cells.
  • As such, current key bottlenecks in the electrosynthesis of nitrogen species out of N2 or air and water are (1) the poor selectivity of the electrocatalyst, and (2) the electrochemical system (electrode, membranes, reactor) is not optimal for long term (continuous) operation, which is eventually needed for an economic viable process. Both factors limit the desired/achieved currents or productivity of ammonia and HA, hampering applicability, operation and upscaling of this process.
  • It is an objective of the present invention to address the aforementioned problems and to provide a process and electrolyzer to efficiently convert reactants such as NO3 -, NO2 -, NOx and N2 into commercially interesting nitrogen species such as ammonia and HA.
    • SUMMARY OF THE INVENTION
  • In a first aspect the present invention provides an electrochemical flow reactor configured for paired electrosynthesis of NH3 and/or Hydroxylamine (HA), said reactor comprising metal electrocatalyst based porous gas diffusion electrodes (GDEs) as cathode and anode.
  • In an embodiment, the electrochemical flow cell reactor is characterized in that the metal electrocatalysts are selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  • In a particular embodiment the metal electrocatalysts of the cathode and the metal electrocatalysts of the anode are different. Hence in an embodiment the metal electrocatalysts of the cathode are selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  • In a preferred embodiment the metal electrocatalysts of the cathode is selected from a Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, Nickel, and Palladium; more in particular the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, and Nickel,
  • In another preferred embodiment the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, Palladium, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy; more in particular the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy.
  • The electrochemical flow cell reactor will typically comprise an anode and a cathode compartment separated by an ion exchange membrane or a one-compartment system where the cathode and anode are not separated from each other. The person skilled in the art is aware of the ion exchange membrane separators used in electrochemical flow cell reactors, including cation exchange membranes, anion exchange membranes and bipolar membranes. Making use of metal electrocatalyst based porous GDEs as anode and cathode, said anode and cathode compartment each preferably comprise an electrolyte compartment and a gas compartment separated from one another by means of the metal electrocatalyst based porous GDEs, configured for gas from the gas compartment to reach the metal electrocatalyst from the GDEs, wherein the metal electrocatalyst is configured to be in contact with the electrolyte from the electrolyte compartment.
  • In an embodiment, the electrolyte compartment of the anode compartment and the electrolyte compartment of the cathode compartment comprise a common electrolyte (either an alkaline or acidic electrolyte; in particular alkaline), wherein the outlet of the electrolyte compartment of the anode compartment is fluidly connected to the inlet of the electrolyte compartment of the cathode compartment. As such a continuous flow of the electrolyte can be realized. In the electrochemical synthesis of NH3 and HA, the gas compartment of the anode compartment and the gas compartment of the cathode compartment comprise a gas inlet for a Nitrogen containing gas (such as N2, NO, NO2, N2O and mixtures thereof), in particular dinitrogen (N2) gas.
  • In a further aspect the present invention provides an electrochemical flow cell reactor for paired electrosynthesis of NH3 and/or Hydroxylamine (HA) from a Nitrogen containing gas, wherein the dinitrogen (N2) from the Nitrogen containing gas from a gas compartment of the anode compartment is oxidized at the anode with the formation of NOx, Nitrate (NO3 -) and/or Nitrite (NO2 -) in the electrolyte of the anode compartment, wherein the thus obtained Nitrate (NO3 -) containing electrolyte is fed into to electrolyte compartment of the cathode compartment, to be reduced at the cathode together with the Nitrogen (N2) from the Nitrogen containing gas from the gas compartment of the cathode compartment with the formation of Ammonia (NH3) and/or hydroxylamine (HA) in the electrolyte of the cathode compartment, and removing the thus obtained Ammonia (NH3) and/or hydroxylamine (HA) containing electrolyte from the electrolyte compartment of the cathode compartment.
  • In an embodiment the electrochemical flow cell reactor, further comprising a separator to retrieve the Ammonia (NH3) and/or hydroxylamine (HA) from the Ammonia (NH3) and/or hydroxylamine (HA) containing electrolyte, and recycling the electrolyte into the electrolyte compartment of the anode compartment.
  • In a second aspect the present invention provides a method of paired electrosynthesis of NH3 and/or Hydroxylamine (HA) in an electrochemical flow cell reactor comprising an anode and a cathode compartment separated by an ion exchange membrane, said method comprising;
    • oxidizing diNitrogen (N2) from a Nitrogen containing gas using a metal electrocatalyst based porous gas diffusion electrodes (GDEs) as anode with the formation of Nitrate (NO3-) and/or Nitrite (NO2 -) in an electrolyte present in an electrolyte compartment of the anode compartment or NOx in the gas compartment of the anode compartment,
    • feeding the thus obtained Nitrate (NO3-)/Nitrite (NO2 -)/NOx containing electrolyte into an electrolyte compartment of the cathode compartment,
    • reducing the Nitrate (NO3-)/Nitrite (NO2 -) from said Nitrate (NO3-) containing electrolyte together with Nitrogen (N2) from a Nitrogen containing gas using a metal electrocatalyst based porous gas diffusion electrodes (GDEs) as cathode, with the formation of Ammonia (NH3) and hydroxylamine (HA) in the alkaline/acidic electrolyte of the cathode compartment, and
    • removing the thus obtained Ammonia (NH3) and hydroxylamine (HA) containing electrolyte from the electrolyte compartment of the cathode compartment.
  • In an embodiment the method of paired electrosynthesis of NH3 and/or Hydroxylamine (HA), further comprising;
    • separating the Ammonia (NH3) and hydroxylamine (HA) from the Ammonia (NH3) and hydroxylamine (HA) containing electrolyte, and
    • recycling the electrolyte into the electrolyte compartment of the anode compartment.
  • In an embodiment the method of paired electrosynthesis of NH3 and/or Hydroxylamine (HA), is characterized in that the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and wherein the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • Figure 1 , herein also referred to as Fig. 1, provides a schematic diagram of the paired electrosynthesis process for NH3 / HA production.
    • DETAILED DESCRIPTION OF THE INVENTION
  • As mentioned herein before, the present invention is in particular directed to a paired electrosynthesis process for the (co)production of hydroxylamine (HA) and/or ammonia out of N2 or air and water. It provides thereto a continuous flow process and a continuous electrochemical flow reactor with porous electrodes at both the anode and the cathode, wherein each of said porous electrodes comprise a metal electrocatalyst layer.
  • Per reference to Fig.1, and further detailed hereinafter, such continuous electrochemical flow reactor consists of a membrane or diaphragm, separating the anode and the cathode compartment and at either side a metal electrocatalyst layer incorporated in a gas diffusion electrode (GDE) to enhance mass transport and increase the electrochemical active surface area.
  • Since a proper Nitrate (NO3 -) source is hard to get (waste water can be used, however, the concentration of nitrates and nitrites herein are typically too low to produce large amounts of ammonia and/or HA) the technical realization of an electrochemical process for HA and/or ammonia synthesis has thus far been hindered by;
    • very low current densities, in particular at the cathode (thus low productivity),
    • poor product selectivity of the electrocatalyst for NRR towards HA or ammonia,
    • large overpotentials due to the anodic reaction, typically oxygen evolution reaction (hence low energetic efficiency),
    • process durability which is a result of the interplay of simultaneous processes occurring on both electrodes, and crossover of species through the membrane, and
    • stability of the electrode structure.
  • This problem has been solved by the paired electrosynthesis process and the continuous electrochemical flow reactor according to the invention. Using a paired electrosynthesis process, wherein the anodic reaction produces nitrates, nitrites and/or NOx which are subsequently used as reactant for the cathodic reaction to produce NH3 and/or HA, the aforementioned problem of a proper Nitrate (NO3 -) source has been resolved. With the reactor of the present invention a N2-containing gas, such as air can be used instead, or even a gaseous reactant, such as NOx can be utilized, optionally together with an electrolyte based on liquid reactants or dissolved species such as NO3 -, NO2 - and N2H4. Using a paired electrosynthesis process, wherein the anodic reaction produces nitrates, nitrites and/or NOx which are subsequently used as reactant for the cathodic reaction to produce NH3 or HA, also results in a decreased cell potential, and thus the energy efficiency is increased. The invention also benefits from a synergistic effect by co-reduction of N2 and NO3 - or NO2 - at the cathode which can be controlled by the potential window. Compared to the existing technologies, this results in high product yields of HA and/or ammonia.
  • Expressed differently, the present invention utilizes the anode reaction products in a paired electrosynthesis concept for the production of HA and ammonia. Although there have been electrodes reported for NRR to ammonia, there are no indications in the literature to co-produce with 100% selectivity only ammonia or HA. Nitrogen oxidation has not been carried out electrochemically in a continuous flow cell which is the key of our anode reaction. It is accordingly an object of the present invention to provide the use of Nitrogen oxidation, i.e. the Electrochemical Nitrogen Oxidation Reaction (NOR), in the electrochemical synthesis of ammonia and/or hydroxylamine, more in particular the use of NOR in a continuous flow cell configuration, in the electrochemical synthesis of ammonia and/or hydroxylamine. The present invention accordingly provides for the use of the products obtained from the anodic oxidation of Nitrogen as reactant for a cathodic reaction to produce NH3 and/or HA. In an embodiment the present invention accordingly provides for the use of the products obtained from the anodic oxidation of Nitrogen in a continuous flow cell, as reactant for a cathodic reaction to produce NH3 and/or HA, more in particular as reactant for a cathodic reaction to produce NH3 and/or HA in a continuous flow cell.
  • Fig. 1 provides a schematic diagram for the paired electrosynthesis of ammonia and/or HA in a continuous electrochemical flow cell reactor (1) using the anodic reaction products as reactant for the cathodic reduction. The electrochemical flow cell reactor comprises an anode compartment (2) and a cathode compartment (3) separated from one another by an ion exchange membrane (4). Both the anode compartment and the cathode compartment are configured as a continuous flow cell, and accordingly comprise an electrolyte compartment (5, 6) comprising a common electrolyte (20) (in the present example an alkaline electrolyte) and a gas compartment (7, 8) separated from one another by means of a metal electrocatalyst based porous GDE (9, 10). The GDE of the anode compartment (9) is configured for N2 containing gas (13) from the gas compartment (7) to reach the metal electrocatalyst layer (11) of the anode which is in contact with the alkaline electrolyte (20) of the anode electrolyte compartment (5). At the interface between said liquid alkaline electrolyte and the metal electrocatalyst layer (11) of the anode, Nitrogen is oxidized with the formation of Nitrate (NO3 -)/Nitrite (NO2 -) in the alkaline electrolyte. The thus obtained Nitrate (NO3 -) containing alkaline electrolyte (21) is fed by means of a fluid connection (19) into the electrolyte compartment of the cathode cell (6). In the cathode compartment (3) another GDE (10) is present and configured for N2 containing gas (14) from the gas compartment (8) the reach the metal electrocatalyst layer (12) of the cathode which is in contact with the Nitrate (NO3 -) containing alkaline electrolyte (21) of the cathode electrolyte compartment (6). At the interface between said Nitrate (NO3 -) containing alkaline electrolyte (21) and the metal electrocatalyst layer (12) of the cathode, Dinitrogen (N2) and/or Nitrate/Nitrite is reduced with the formation of Ammonia (NH3) and/or Hydroxylamine (HA) in the alkaline electrolyte of the cathode compartment. The thus obtained Ammonia (NH3) and/or Hydroxylamine (HA) containing alkaline electrolyte (22) being removed from the cathode electrolyte compartment (6) through an outlet (18). The double arrow symbolises a separator to separate Ammonia (NH3) and/or Hydroxylamine (HA) from the Ammonia (NH3) and/or Hydroxylamine (HA) containing alkaline electrolyte (22), with possible recycling of the alkaline electrolyte (20) into the electrolyte compartment of the anode (5). The recycling of the alkaline electrolyte (20) is an optional step in the method as disclosed. Also the separator as used, is simply to indicate any possible means and procedures to obtain the reaction products Ammonia (NH3) and/or Hydroxylamine (HA), from the Ammonia (NH3) and/or Hydroxylamine (HA) containing alkaline electrolyte (22).
  • In this schematic representation the alkaline electrolyte is an aqueous alkaline electrolyte, hence the electrochemical flow cell reactor may also act as an electrolyzer with the formation of Oxygen (O2) gas at the anode and Hydrogen (H2) gas at the cathode. However, via selective electrocatalysts and selecting the optimal reaction conditions (potential, electrolyte composition, etc.) these side reactions are minimized. Also at either side the formation or consumption of NOx gasses cannot be excluded.
    • Abbreviations
    • CL - Catalyst layer
    • GDE - Gas Diffusion Electrode
    • GDL - Gas Diffusion Layer
    • HA- Hydroxylamine
    • HER - Hydrogen Evolution Reaction
    • NRR - Electrochemical Nitrogen Reduction Reaction
    • NOR - Electrochemical Nitrogen Oxidation Reaction
    • NO3RR - Electrochemical Nitrate Reduction Reaction
    • NO2RR - Electrochemical Nitrite Reduction Reaction
    • OER - Oxygen Evolution Reaction
    • ORR - Oxygen Reduction Reaction
    Reference Numbers
    • 1 -
    electrochemical flow cell reactor
    2 -
    anode compartment, also known as anode cell
    3 -
    cathode compartment, also known as cathode cell
    4 -
    membrane
    5 -
    electrolyte compartment of the anode cell
    6 -
    electrolyte compartment of the cathode cell
    7 -
    gas compartment of the anode cell
    8 -
    gas compartment of the cathode cell
    9 -
    GDE of the anode cell or the anode GDE
    10 -
    GDE of the cathode cell or the cathode GDE
    11 -
    the metal electrocatalyst layer of the anode GDE
    12 -
    the metal electrocatalyst layer of the cathode GDE
    13 -
    gas input to the gas compartment of the anode cell
    14 -
    gas input to the gas compartment of the cathode cell
    15 -
    electrolyte inlet to the electrolyte compartment of the anode cell
    16 -
    electrolyte outlet of the electrolyte compartment of the anode cell
    17 -
    electrolyte inlet to the electrolyte compartment of the cathode cell
    18 -
    electrolyte outlet of the electrolyte compartment of the cathode cell
    19 -
    fluid connection between the electrolyte compartments
    20 -
    alkaline electrolyte
    21 -
    Nitrate (NO3 -)/nitrite (NO2 -) containing alkaline electrolyte
    22 -
    Ammonia (NH3) and/or Hydroxylamine (HA) containing alkaline electrolyte

Claims (14)

  1. An electrochemical flow reactor configured for paired electrosynthesis of NH3 and/or Hydroxylamine (HA), said reactor comprising metal electrocatalyst based porous gas diffusion electrodes (GDEs) as cathode and anode.
  2. The electrochemical flow cell reactor according to claim 1, wherein the metal electrocatalysts are selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  3. The electrochemical flow cell reactor according to claims 1 or 2, wherein the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and wherein the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
  4. The electrochemical flow cell reactor according to claim 1, wherein the metal electrocatalysts of the cathode is selected from a Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, Nickel, and Palladium; more in particular the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate alloy, Copper, a Platinum/Ruthenium alloy, a Platinum/Tin alloy, Cobalt, and Nickel,
  5. The electrochemical flow cell reactor according to claim 1, wherein the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, Palladium, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy; more in particular the metal electrocatalysts of the anode is selected from Platinum, a Ruthenium/Titanium alloy, a Cobalt/Iron/Zinc/Oxide alloy, an Iron/Tin alloy, and a Palladium/Ruthenium alloy
  6. The electrochemical flow cell reactor according to any one of the preceding claims, further comprising an anode and a cathode compartment separated by an ion exchange membrane or a compartment in which the anode and cathode are not separated from each other.
  7. The electrochemical flow cell reactor according to claim 6, wherein the anode and cathode compartment each comprise an electrolyte compartment and a gas compartment separated from one another by means of the metal electrocatalyst based porous GDEs, configured for gas from the gas compartment to reach the metal electrocatalyst from the GDEs, configured to be in contact with the electrolyte from the electrolyte compartment.
  8. The electrochemical flow cell reactor according to claim 7, wherein the electrolyte compartment of the anode compartment and the electrolyte compartment of the cathode compartment comprise a common electrolyte, and wherein the outlet of the electrolyte compartment of the anode compartment is fluidly connected to the inlet of the electrolyte compartment of the cathode compartment.
  9. The electrochemical flow cell reactor according to claim 7, wherein the gas compartment of the anode compartment and the gas compartment of the cathode compartment comprise a gas inlet for a Nitrogen (N2) containing gas.
  10. The electrochemical flow cell reactor according to claim 9, wherein the Nitrogen (N2) from the Nitrogen containing gas from the gas compartment of the anode compartment is oxidized at the anode with the formation of Nitrate (NO3 -), Nitrite (NO2 -) and/or NOx in the electrolyte of the anode compartment, wherein the thus obtained Nitrate (NO3 -) containing electrolyte is fed into to electrolyte compartment of the cathode compartment, to be reduced at the cathode together with the Nitrogen (N2) from the Nitrogen containing gas from the gas compartment of the cathode compartment with the formation of Ammonia (NH3) and hydroxylamine (HA) in the electrolyte of the cathode compartment, and removing the thus obtained Ammonia (NH3) and hydroxylamine (HA) containing electrolyte from the electrolyte compartment of the cathode compartment.
  11. The electrochemical flow cell reactor according to claim 10, further comprising a separator to retrieve the Ammonia (NH3) and hydroxylamine (HA) from the Ammonia (NH3) and hydroxylamine (HA) containing electrolyte, and recycling the electrolyte into the electrolyte compartment of the anode compartment.
  12. A method of paired electrosynthesis of NH3 and/or Hydroxylamine (HA) in an electrochemical flow cell reactor comprising an anode and a cathode compartment separated by an ion exchange membrane, said method comprising;
    • oxidizing Dinitrogen (N2) from a Nitrogen containing gas using a metal electrocatalyst based porous gas diffusion electrodes (GDEs) as anode with the formation of Nitrate (NO3 -), Nitrite (NO2 -) and/or NOx in an alkaline or acidic electrolyte present in an electrolyte compartment of the anode compartment,
    • feeding the thus obtained Nitrate (NO3 -) containing alkaline/acidic electrolyte into an electrolyte compartment of the cathode compartment,
    • reducing the Nitrate (NO3 -) from said Nitrate (NO3 -) containing alkaline electrolyte together with Dinitrogen (N2) from a Nitrogen containing gas using a metal electrocatalyst based porous gas diffusion electrodes (GDEs) as cathode, with the formation of Ammonia (NH3) and hydroxylamine (HA) in the alkaline/acidic electrolyte of the cathode compartment, and
    • removing the thus obtained Ammonia (NH3) and hydroxylamine (HA) containing alkaline/acidic electrolyte from the electrolyte compartment of the cathode compartment.
  13. The method of paired electrosynthesis of NH3 and/or Hydroxylamine (HA) according to claim 12, further comprising;
    • separating the Ammonia (NH3) and hydroxylamine (HA) from the Ammonia (NH3) and hydroxylamine (HA) containing alkaline electrolyte, and
    • recycling the alkaline electrolyte into the electrolyte compartment of the anode compartment.
  14. The method of claims 12 or 13, wherein the metal electrocatalysts of the cathode is selected from Bismuth/Molybdate based catalysts, Copper based catalysts, Ruthenium based catalysts, Platinum based catalysts, Cobalt based catalysts, Nickel based catalysts, Palladium based catalysts, and combinations thereof; and wherein the metal electrocatalysts of the anode is selected from Ruthenium based catalysts, Platinum based catalysts, Palladium based catalysts, Cobalt/Iron/Zinc/Oxide alloy based catalysts, Iron/Tin alloy based catalysts and combinations thereof.
EP22195550.3A 2022-09-14 2022-09-14 Paired electrosynthesis process for (co)production hydroxylamine and ammonia Pending EP4339326A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22195550.3A EP4339326A1 (en) 2022-09-14 2022-09-14 Paired electrosynthesis process for (co)production hydroxylamine and ammonia
PCT/EP2023/075120 WO2024056718A2 (en) 2022-09-14 2023-09-13 Paired electrosynthesis process for (co)production hydroxylamine and ammonia

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22195550.3A EP4339326A1 (en) 2022-09-14 2022-09-14 Paired electrosynthesis process for (co)production hydroxylamine and ammonia

Publications (1)

Publication Number Publication Date
EP4339326A1 true EP4339326A1 (en) 2024-03-20

Family

ID=83318730

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22195550.3A Pending EP4339326A1 (en) 2022-09-14 2022-09-14 Paired electrosynthesis process for (co)production hydroxylamine and ammonia

Country Status (2)

Country Link
EP (1) EP4339326A1 (en)
WO (1) WO2024056718A2 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5447610A (en) * 1994-06-23 1995-09-05 Sachem, Inc. Electrolytic conversion of nitrogen oxides to hydroxylamine and hydroxylammonium salts
WO1999009234A2 (en) * 1997-08-15 1999-02-25 Sachem, Inc. Electrosynthesis of hydroxylammonium salts and hydroxylamine using a mediator, a catalytic film, methods of making the catalytic film, and electrosynthesis of compounds using the catalytic film
WO2012051507A2 (en) * 2010-10-15 2012-04-19 Energy & Environmental Research Center Foundation Electrochemical process for the preparation of nitrogen fertilizers
US20210340683A1 (en) * 2020-05-01 2021-11-04 University Of Tennessee Research Foundation Development of ruthenium-copper nano-sponge electrodes for ambient electrochemical reduction of nitrogen to ammonia
WO2022060920A2 (en) * 2020-09-16 2022-03-24 The Board Of Trustees Of The University Of Illinois Device and methods for production of ammonia and nitrates under ambient conditions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5447610A (en) * 1994-06-23 1995-09-05 Sachem, Inc. Electrolytic conversion of nitrogen oxides to hydroxylamine and hydroxylammonium salts
WO1999009234A2 (en) * 1997-08-15 1999-02-25 Sachem, Inc. Electrosynthesis of hydroxylammonium salts and hydroxylamine using a mediator, a catalytic film, methods of making the catalytic film, and electrosynthesis of compounds using the catalytic film
WO2012051507A2 (en) * 2010-10-15 2012-04-19 Energy & Environmental Research Center Foundation Electrochemical process for the preparation of nitrogen fertilizers
US20210340683A1 (en) * 2020-05-01 2021-11-04 University Of Tennessee Research Foundation Development of ruthenium-copper nano-sponge electrodes for ambient electrochemical reduction of nitrogen to ammonia
WO2022060920A2 (en) * 2020-09-16 2022-03-24 The Board Of Trustees Of The University Of Illinois Device and methods for production of ammonia and nitrates under ambient conditions

Also Published As

Publication number Publication date
WO2024056718A2 (en) 2024-03-21

Similar Documents

Publication Publication Date Title
US11390954B2 (en) Multi-step process and system for converting carbon dioxide to multi-carbon products
Jeng et al. Investigation of CO 2 single-pass conversion in a flow electrolyzer
US4311569A (en) Device for evolution of oxygen with ternary electrocatalysts containing valve metals
US9518329B2 (en) Method for electrochemically converting carbon dioxide
EP2978874B1 (en) Electrochemical synthesis of ammonia in alkaline media
US9217202B2 (en) Membrane reactor
US4528083A (en) Device for evolution of oxygen with ternary electrocatalysts containing valve metals
CN110117794B (en) Electro-reduction of CO2Three-chamber type electrolytic cell device for preparing formate and electrolytic method thereof
IL288368A (en) Modular electrolyzer stack and process to convert carbon dioxide to gaseous products at elevated pressure and with high conversion rate
KR102186440B1 (en) Electrochemical Ammonia Synthesis Method Using Recycling Process
JPH03111587A (en) Electrolytic bath for reduction of carbon dioxide
US9145614B2 (en) Membrane reactor
US20030049509A1 (en) Alkaline direct methanol fuel cell
EP4339326A1 (en) Paired electrosynthesis process for (co)production hydroxylamine and ammonia
Zhang et al. Electrolytic Conversion of Bicarbonate Solutions to CO At> 500 mA cm− 2 and 2.2 V
Machida et al. Electrocatalytic nitrate hydrogenation over an H+-conducting solid polymer electrolyte membrane–modified cathode assembly
CN216947223U (en) Carbon dioxide electrolysis device
US20210189572A1 (en) Production and separation of phosgene by means of a combined co2 and chloride electrolysis
CN114402095B (en) Cross-flow water electrolysis
CN113416972A (en) Device and method for producing hydrogen by electrolyzing water step by step based on all-vanadium liquid flow redox medium
PESSELMAN et al. Electrogenerative oxidation of ethanol to acetaldehyde
Lewdorowicz et al. Synthesis of hydroxylamine in the nitric oxide-Hydrogen fuel cell
Graça et al. Electrochemical ammonia synthesis: Mechanism, recent developments, and challenges in catalyst design
KR102386012B1 (en) Self-driving electrochemical cell
US20240162517A1 (en) Battery recycling apparatus and method

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR