A method for producing green ammonia using a microdroplet reaction based on water and nitrogen gas, and a confinement catalyst reaction at the gas-liquid interface.

Abstract

A method for producing green ammonia using a microdroplet reaction based on water and nitrogen gas, and a confinement catalyst reaction at the gas-liquid interface, comprises the steps of: mixing water with a modifier selected from nanomaterials, conductive polymers, and inorganic salts to obtain an aqueous solution; and supplying the aqueous solution to a microdroplet generator to produce microdroplets with a size of 10 μm or less. The strong electric field of the electric double layer at the gas-liquid interface of the microdroplets is utilized to spontaneously generate hydrogen radicals and hydroxyl radicals. Under a nitrogen gas atmosphere, a large amount of hydrogen radicals and nitrogen gas in the gas phase undergo a radical chain reaction at the gas-liquid interface to produce ammonia, and hydroxyl radicals combine to produce hydrogen peroxide. This method is simple, environmentally friendly, not limited by catalysts, and can meet the requirements of different production processes simply by providing modifiers with excellent electronic conductivity. It helps meet environmental protection requirements and the strategic needs of hydrogen energy storage in the context of "dual carbon."

Description

[Technical Field]

[0001] This disclosure relates to the technology of green energy, and more particularly to a method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface. [Background technology]

[0002] Ammonia is widely used as an important chemical raw material in fields such as chemical fertilizers, pharmaceuticals, and energy. With the promotion of the "dual carbon" vision, ammonia is recognized as an "energy carrier" and "hydrogen carrier" with significant potential, and breakthroughs in its green synthesis technology are of great importance as they will contribute to the long-term development of hydrogen energy. Currently, industrial ammonia synthesis mainly uses the Haber-Bosch process, which employs Fe-based catalysts and operates under reaction conditions of 350-550°C or higher and 100-300 atm or lower, resulting in high energy consumption, heavy pollution, and demanding equipment and process requirements. Studies show that the Haber-Bosch process emits approximately 670 million tons of CO2 annually, accounting for about 2.4% of total global carbon emissions, creating significant pressure for emission reductions. Therefore, there is an urgent need for new ammonia synthesis technologies that can solve the problem of excessively high carbon emissions in conventional ammonia synthesis processes and ultimately achieve "zero-carbon" emission ammonia production, i.e., green ammonia production.

[0003] In recent years, with the development of the hydrogen energy industry, related technologies have included the production of green ammonia by reacting green hydrogen, produced by electrolysis of water, with nitrogen gas using the improved Habere-Bosch method. Compared to the gray and blue ammonia obtained through conventional industrial processes, this process relies primarily on renewable energy to achieve the fusion of green hydrogen and ammonia, while ammonia plays a crucial role as a liquid organic hydrogen carrier in the subsequent hydrogen industry chain (production, storage, transportation, and utilization). However, the production of green ammonia involves two processes: the production of green hydrogen through water electrolysis and the production of green ammonia through the reaction of nitrogen gas with green hydrogen. While this depends on the spread and cost reduction of renewable energy sources such as wind, solar, and electricity, from the perspective of actual end-use, the cost is still limited by the electricity cost of green hydrogen, further increasing the cost of green ammonia for end-use and limiting its scalability.

[0004] Furthermore, the information disclosed in the background technology described above is intended solely to enhance understanding of the background of this disclosure and may include information that does not constitute prior art known to those skilled in the art. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] This disclosure provides a method for producing green ammonia using a microdroplet reaction based on water and nitrogen gas, and a confinement catalyst reaction at the gas-liquid interface. This method primarily utilizes a microdroplet reaction and a confinement catalyst at the gas-liquid interface to directly produce green ammonia using nitrogen gas and water as direct reactants, through a radical chain reaction involving a microdroplet reaction and a confinement catalyst reaction at the gas-liquid interface. This method provides a new concept and method for addressing the technical challenge of achieving "zero carbon" in the ammonia production process. [Means for solving the problem]

[0006] The present invention provides a method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalyst reaction at the gas-liquid interface. Step S1 involves mixing water with one or more adjusting agents selected from nanomaterials, conductive polymers, and redox-active inorganic salts to obtain an aqueous solution. Step S2 involves supplying an aqueous solution to a microdroplet generating device to generate microdroplets with a size of 10 μm or less, Step S3 involves forming a nitrogen gas atmosphere at the spray end of the aforementioned minute droplets, so that the water and nitrogen gas in the minute droplets spontaneously undergo a radical reaction at the gas-liquid interface to generate ammonia. The process includes step S4 of detecting or collecting the ammonia. Specifically, the ammonia produced may be ammonia gas present in gaseous form or aqueous ammonia present in liquid form.

[0007] Specifically, the essence of the present invention is a radical reaction process in which hydrogen radicals (·H) generated at the gas-liquid interface between nitrogen gas and minute droplets combine to form (·HNN), thereby lowering the activation energy and reaction barrier of the nitrogen gas reaction, and in which hydroxyl radicals in the system form hydrogen peroxide through a self-aligned bonding method, which is specifically as follows.

[0008] H2O → ·H+·OH N2+·H→·HNN ·HNN+·H→·HNNH· ·HNNH+2·H→2NH3 6·OH → 3H2O2

[0009] The complete reaction equation is as follows:

[0010] JPEG2026521856000002.jpg12170

[0011] In one exemplary embodiment of the present disclosure, the microdroplet generating device is selected from an electrospray device, an airspray device, and an ultrasonic atomizing device.

[0012] In one exemplary embodiment of the present disclosure, the micro-droplet generating device is an electrospray device, the electrospray device has an electrospray probe, the flow rate of injecting the aqueous solution into the electrospray probe is 5 to 150 μL / min, and by setting the inner diameter of the electrospray probe to 5 to 150 μm and the applied bias voltage to 3 to 7 kV, micro-droplets with a size of less than 10 μm are generated, and nitrogen gas is supplied to the spraying end of the electrospray probe to form a nitrogen gas atmosphere.

[0013] In one exemplary embodiment of the present disclosure, the electrospray device has a plurality of electrospray probes.

[0014] In one exemplary embodiment of the present disclosure, the micro-droplet generating device is an airspray device, the airspray device includes an inner tube and an outer tube externally fitted outside the inner tube, a spraying end is formed at the end of the inner tube, nitrogen gas is introduced into the outer tube as sheath gas, the aqueous solution is injected into the inner tube, and atomized by the sheath gas to form the micro-droplets, and the sheath gas flows to the spraying end to form the nitrogen gas atmosphere.

[0015] In one exemplary embodiment of the present disclosure, the flow rate of injecting the aqueous solution into the inner tube is 5 to 150 μL / min, the pressure of the nitrogen gas as sheath gas is 60 to 120 psi, and the flight speed of the generated micro-droplets is 65 to 110 m / s.

[0016] In one exemplary embodiment of the present disclosure, the inorganic salt is one or more selected from chloroauric acid, palladium chloride, and chloroauric acid - palladium chloride, the nanomaterial is one or more selected from gold nanoparticles, palladium-coated gold nanoparticles, gold palladium nanocomposites, and magnetic nanoparticles, and the conductive polymer is C 60 -(OH) nOne or more selected from an alkalized polyaniline-gold nanoparticle composite and an acidified polyaniline-gold nanoparticle composite, and the regulator has or can generate an electron conduction effect in the microdroplet reaction.

[0017] In one exemplary embodiment of the present disclosure, when the regulator is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is 50 to 1000 μg / mL, and when the regulator is a nanomaterial or a conductive polymer, the concentration of the nanomaterial or the conductive polymer in the aqueous solution is 10 -5 ~10 -1 mg / mL.

[0018] In one exemplary embodiment of the present disclosure, the step of detecting or collecting the ammonia includes Providing a mass spectrometer at the spray end of the microdroplet generator to receive the product generated at the spray end and perform mass spectrometry, Or Providing a collection device having a sealed collection chamber at the spray end of the microdroplet generator such that the spray end is disposed within the collection chamber, the product being ammonia or an amide, an organic acid being added to the aqueous solution in step S1, and the amide being generated by the reaction of the organic acid and ammonia.

[0019] In one exemplary embodiment of the present disclosure, a conductive plate and / or a heating device is further provided in the collection chamber, and the conductive plate is grounded or connected to a high voltage to remove the charges accumulated in the collection chamber.

[0020] In one exemplary embodiment of the present disclosure, a gas supply pipe and a gas discharge pipe are connected to the collection chamber, nitrogen gas is introduced into the gas supply pipe, and the generated ammonia gas is discharged through the gas discharge pipe.

Advantages of the Invention

[0022] When the green ammonia production method of the present disclosure is implemented, a micro-droplet generator is used to obtain micro-droplets with a diameter less than 10 μm. The micro-droplets have a "confining effect" at the mesoscopic scale and have special physicochemical properties such as a high specific surface area, a high charge density, and a strong electric field of the electric double layer. The micro-droplets, as a micro-reactor, are based on a special gas-liquid interface effect and the action of a strong electric field at the gas-liquid interface (10 7 V / cm), ionize water molecules (H + ) to form hydrogen radicals (·H, H + +e - →·H), and further generate recombination between ·H (2·H→H2). However, since the half-life of the hydrogen radical (·H) is short (<10 -9 s), it immediately undergoes a reverse reaction to form hydrogen ions (·H-e - →H + ). This process is controlled by whether electrons (e - ) move or not. By utilizing the excellent electron transfer properties of conductive metal materials, nano-materials, inorganic salts, etc., the electrons (e - ) generated at the interface can be moved to make the reaction proceed in the forward direction. The hydrogen radicals (·H, H + +e - →·H) accumulate at the gas-liquid interface and recombine with N2 in the gas phase under the action of the strong electric field at the gas-liquid interface to generate a transition state (NNH·), triggering a radical chain reaction to finally generate NH3. Thus, a new green ammonia production method based on the synergistic effect of the three substances of micro-droplets of water, nitrogen gas, and an electron-capable regulator is realized. Also, the combination of hydroxyl radicals (·OH) generates H2O2 (2·OH→H2O2).

[0023] This green ammonia production method differs from conventional methods that use green electricity to produce hydrogen gas and then use hydrogen and nitrogen gases in an improved Haber-Bosch process to produce green ammonia. Instead, it directly uses water and nitrogen gas as raw materials, generating ammonia through the confinement effect of the gas-liquid interface in a microdroplet reaction. Furthermore, the efficiency of ammonia production can be significantly improved with the use of a modifier (683.9 mmol / gh). Therefore, this method is green, environmentally friendly, has low energy consumption costs, and directly produces ammonia using water and nitrogen gas under "zero-carbon" conditions, opening up a new approach to the production and manufacture of green ammonia.

[0024] It should be understood that the above general explanation and the detailed explanation below are illustrative and explanatory only and do not limit the scope of this disclosure. [Brief explanation of the drawing]

[0025] To more clearly illustrate the technical means in the embodiments of this disclosure, the following drawings necessary for the embodiments are briefly described below. It should be understood that these drawings clearly illustrate only some embodiments of this disclosure and are not limiting in scope. Those skilled in the art can obtain other relevant drawings from these drawings without any creative effort.

[0026] [Figure 1] This is a flowchart of a method for producing green ammonia using a microdroplet reaction based on water and nitrogen gas and a confinement catalyst reaction at the gas-liquid interface, according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of an air spray device according to one embodiment of the present disclosure. [Figure 3] This is a schematic diagram of a receiving device and mass spectrometer according to one embodiment of the present disclosure. [Figure 4] This is a schematic diagram of a collection device according to one embodiment of the present disclosure. [Figure 5]These are the mass spectra in the negative ion mode and positive ion mode of a microdroplet produced from an aqueous fumaric acid solution according to Example 1 of this disclosure. [Figure 6] This is the mass spectrum in positive ion mode of microdroplets generated from aqueous solutions a to d according to Example 1 of this disclosure. [Figure 7] These are mass spectra obtained from microdroplets generated from the negative control, pure water, and aqueous solutions a-d according to Example 2 of this disclosure. [Modes for carrying out the invention]

[0027] To further clarify the purpose, technical means, and advantages of the embodiments of this disclosure, the technical means in the embodiments of this disclosure are described below clearly and completely. Unless otherwise specified, the embodiments are carried out under general conditions or conditions suggested by the manufacturer. Unless otherwise specified, the reagents and equipment used are all commercially available common products.

[0028] The following describes in detail the method for producing green ammonia based on a microdroplet reaction according to the embodiments of this disclosure.

[0029] As shown in Figure 1, the method for producing green ammonia according to an embodiment of the present invention, which involves a microdroplet reaction based on water and nitrogen gas and a confinement catalyst reaction at the gas-liquid interface, Step S1 involves mixing water with one or more adjusting agents selected from nanomaterials, conductive polymers, and redox-active inorganic salts to obtain an aqueous solution. Step S2 involves supplying an aqueous solution to a microdroplet generating device to generate microdroplets with a size of 10 μm or less, Step S3 involves forming a nitrogen gas atmosphere at the spray end of the above-mentioned minute droplets, so that the water and nitrogen gas in the above-mentioned minute droplets spontaneously undergo a radical reaction at the gas-liquid interface to generate ammonia. The process includes step S4 of detecting or collecting the above-mentioned ammonia.

[0030] Microdroplet reactions primarily rely on the use of droplets smaller than 10 μm in size, generated under external force, as microreactors. Due to a different recognition mechanism than bulk reactions, they break the conventional recognition of water as a solvent at the macroscopic physicochemical scale, resulting in special physicochemical properties such as increased specific surface area, strong interfacial electric fields, reduced reaction barriers, and unique redox characteristics. Compared to the macroscopic scale, the electric field strength between microdroplets under microscopic conditions and the gas-liquid interface at the mesoscopic scale (i.e., under confinement conditions) is 10 μm. 7 It has a strong electrical double layer that reaches V / cm and can induce HER (hydrogen evolution reaction) and OER (oxygen evolution reaction) reactions on a mesoscopic scale. Depending on the electrochemical catalytic reaction characteristics, the catalytic effect at the gas-liquid interface of the microdroplets can be enhanced under the action of a special dielectric material, thereby forming a confined catalytic reaction system at the gas-liquid interface. In the green ammonia production method according to this embodiment, microdroplets are used as microreactors, and an electron conductor is introduced into the microreactor using a specific adjusting agent to selectively adjust the thickness or conductivity of the electrical double layer, thereby improving the electron exfoliation efficiency and promoting the bonding of nitrogen gas with hydrogen radicals generated at the gas-liquid interface of the microdroplets, converting them into ammonia gas.

[0031] In one embodiment of this disclosure, in step S1, the inorganic salt is one or more selected from chloroauric acid (HAuCl4), palladium chloride (PdCl2), and chloroauric acid-palladium chloride (HAuCl4-PdCl2). The oxidation-reduction action of the inorganic salt improves the gas-liquid interface properties of the microdroplets and improves the efficiency of ammonia production.

[0032] In one embodiment of this disclosure, the nanomaterial is one or more selected from (Au NPs), palladium-coated gold nanoparticles (Au@Pd NPs), gold-palladium alloy nanoparticles (AuPd alloy NPs), and magnetic nanoparticles. Specifically, the magnetic nanoparticles may be, for example, iron(III) oxide nanoparticles (Fe3O4 NPs).

[0033] In one embodiment of the present disclosure, the conductive polymer is C60 -(OH)n, one or more selected from alkalized polyaniline-gold nanoparticle composites (PANI@AuNPs-NaOH) and acidified polyaniline-gold nanoparticle composites (PANI@AuNPs-HCl). By adding the above nanoparticles, the interfacial effect can be enhanced, the thickness of the electric double layer can be adjusted, the electron exfoliation efficiency can be changed, and ammonia generation can be promoted.

[0034] Specifically, C 60 -(OH)n is C 60 These are polyhydroxy compounds, also known as fullerenes, and because they have multiple hydroxyl groups in their molecule, they are readily soluble in water and can be synthesized, for example, by an amine catalyst. ANI@AuNPs-NaOH and PANI@AuNPs-HCl can be obtained by conventional manufacturing methods. For example, in one example, 3.5 mL of 55 nm gold nanoparticles were dispersed in 1.5 mL of 2 mM aniline and 0.25 mL of 40 mM SDS solution, shaken for 1 min in a vortex mixer, 1.5 mL of 2 mM (NH4)2S2O8-HCl aqueous solution was added, and the mixture was uniformly mixed for 10 s in a vortex shaker. The reaction was then allowed to proceed at room temperature for 12 hours, during which time the aniline in the system polymerized to coat the surface of the gold nanoparticles, forming an aqueous solution of gold nanoparticles coated with a polymer approximately 16 nm thick. This solution was then centrifuged and washed to obtain PANI@AuNPs-HCl. PANI@AuNPs-HCl particles were dispersed in an aqueous solution, a 2M NaOH solution was added to adjust the pH of the solution to 11.4, and the solution was magnetically stirred for 2 hours to obtain PANI@AuNPs-NaOH.

[0035] In one embodiment of this disclosure, when the adjusting agent is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is 50 to 1000 μg / mL, and when the adjusting agent is a nanomaterial or a conductive polymer, the concentration of the nanomaterial or conductive polymer in the aqueous solution is 10 -5 ~10 -1 The concentration is mg / mL. If the concentration of the adjusting agent is different, different concentrations of ammonia will be produced in the reaction system.

[0036] Furthermore, in one embodiment of the present disclosure, the adjusting agent is HAuCl4, PdCl2, or HAuCl4-PdCl2, and the concentration of the adjusting agent in the aqueous solution is 500 μg / mL, at which concentration the ammonia yield reaches 98 mmol / gh or more. Furthermore, when the adjusting agent is AuPd alloy NPs, the concentration of AuPd alloy NPs in the aqueous solution is 10 -2 At a concentration of mg / mL, the ammonia yield reaches 683.9 mmol / gh or higher. There is a certain difference in ammonia production efficiency between inorganic salts and nanoalloys, with nanoalloys exhibiting superior ammonia production ability. On the other hand, nanoalloys have excellent electron-exfoliating properties, which promote the generation of hydrogen radicals (·H) and allow them to react with nitrogen gas at the gas-liquid interface. On the other hand, inorganic salts function as sacrificial agents, resulting in redox reactions (3H + HAuCl4 → Au + 4HCl, 2H + PdCl2 → Pd + 2HCl) between the hydrogen radicals and the inorganic salt system, and exhibiting a depleting effect on the hydrogen radicals (·H).

[0037] In one embodiment of the present disclosure, the microdroplet generation apparatus is selected from an electrospray apparatus, an air spray apparatus, and an ultrasonic atomizer. The specific structures of the electrospray apparatus, air spray apparatus, and ultrasonic atomizer can be referenced from the prior art, for example, the specific structure of the electrospray apparatus can be referenced from an electrospray apparatus in mass spectrometry.

[0038] In one specific embodiment, the electrospray apparatus may include a syringe, a connector, an electrospray probe, and a high-voltage power supply. The connector is, for example, a straight connector, and the syringe and the electrospray probe are connected via the connector, with the aqueous solution entering the electrospray probe through the syringe. The high-voltage power supply creates an electric field at the spray end of the electrospray probe, and the aqueous solution is atomized according to the principles of electrohydrodynamics to form microdroplets. By supplying nitrogen gas around the electrospray probe, the nitrogen gas and the microdroplets undergo a radical chain reaction to produce ammonia gas or ammonia water.

[0039] Furthermore, the electrospray apparatus may be equipped with multiple electrospray probes arranged in parallel, and these multiple electrospray probes may be connected to the same syringe, or each electrospray probe may be connected to a single syringe. The multiple electrospray probes arranged in parallel effectively improve the ammonia production efficiency.

[0040] Furthermore, by injecting the aqueous solution into the electrospray probe at a flow rate of 5-150 μL / min, setting the inner diameter of the electrospray probe to 5-150 μm, and applying a bias voltage of 3-7 kV, minute droplets smaller than 10 μm are generated. Nitrogen gas is supplied to the spray end of the electrospray probe using a device such as a gas cylinder to create a nitrogen gas atmosphere, and a radical chain reaction between the nitrogen gas and the minute droplets is realized to generate ammonia gas or aqueous ammonia. With the above parameters, in the spatial dimension, the size of the generated minute droplets is small, and the aqueous solution per unit volume has a high or the highest specific surface area, thereby increasing the probability of contact between the nitrogen gas and the gas-liquid interface. In the temporal dimension, the reaction time of the nitrogen gas at the gas-liquid interface of the minute droplets is extended. These effects in the spatial and temporal dimensions help to improve the rate and efficiency of ammonia generation by minute droplets.

[0041] In one specific embodiment, as shown in Figure 2, the air spray device 200 may include an inner tube 210 and an outer tube 220 fitted to the outside of the inner tube 210. A gas cylinder 230 supplying a sheath gas (nitrogen gas) at different pressures is connected to the outer tube 220, and a syringe (not shown) is connected to one end of the inner tube 210. The other end forms a spray end 240. Specifically, the inner diameter of the inner tube gradually decreases, forming a spray end at the end. The aqueous solution enters the inner tube 210 through the syringe and forms minute droplets at the spray end under the action of air atomization. The sheath gas also flows to the spray end 240, forming the nitrogen gas atmosphere.

[0042] Furthermore, the flow rate of the aqueous solution injected into the inner tube is 5-150 μL / min, the pressure of the nitrogen gas used as the sheath gas is 60-120 psi, and the flight velocity of the generated microdroplets is 65-110 m / s. More preferably, the flight velocity of the generated microdroplets is 80-90 m / s. Under these parameters, the ammonia generation rate is higher.

[0043] In one specific embodiment, the ultrasonic atomizing device includes a syringe, an ultrasonic generator, and a spray head. The ultrasonic generator generates ultrasonic vibration waves, and under the action of the ultrasonic vibration waves, the aqueous solution is atomized into minute droplets. Nitrogen gas is supplied around the minute droplets by a device such as a gas cylinder to form a nitrogen gas atmosphere.

[0044] In one embodiment of the present disclosure, in step S4, the generated ammonia gas or ammonia water is detected. Specifically, the step of detecting ammonia includes providing a mass spectrometer at the spray end of the microdroplet generator to receive the product generated at the spray end of the microdroplet generator and perform mass spectrometry.

[0045] Specifically, in one embodiment, the product may be ammonia, which is received by a receiving device and then supplied to a mass spectrometer for detection. Figure 3 is a diagram of a device for receiving and detecting ammonia in one example. As shown in Figure 3, the receiving device 310 has a sealed receiving chamber 311 (in an air environment), and the spray end 321 of a microdroplet generator (electrospray device or air spray device) is inserted into the receiving chamber 311. The receiving chamber 311 can be made from, for example, a round-bottom flask. The receiving chamber 311 has a transport pipe 312 that transports the ammonia gas in the chamber to the mass spectrometer. A cooling chamber 330 is provided outside the receiving chamber 311. The receiving chamber 311 is placed inside the cooling chamber 330, and the cooling chamber 330 is filled with a refrigerant to form a cold trap system that cools and solidifies the moisture formed during the spraying process. The gas discharge pipe 212 transports the generated ammonia gas to the mass spectrometer 340 for online detection.

[0046] Furthermore, in one embodiment of the present disclosure, a refrigerant is provided outside the collection chamber to cool and solidify the water formed during the spraying process, and the refrigerant is one or more selected from liquid nitrogen, ice water, ice-containing brine, and ethylene glycol. By providing a refrigerant, the influence of water in the microdroplets on the mass spectrometer can be effectively eliminated during the real-time and online mass spectrometry process.

[0047] Specifically, in another embodiment, the product in the step of detecting ammonia may be an amide. Specifically, to facilitate detection, an organic acid may be added to the aqueous solution in step S1 so that ammonia generated from nitrogen gas at the gas-liquid interface of the microdroplets reacts with the organic acid in the microdroplets to produce an amide compound. The ammonia in the system is indirectly measured by detecting the amide compound in the positive ion mode of mass spectrometry. For example, in one example, fumaric acid is added to an aqueous solution and microdroplets are generated using an air spray device. The organic acid in the microdroplets generated by air atomization reacts with ammonia to produce an amide compound, and hydrogen peroxide is also produced. By detecting the amide compound with a mass spectrometer, it is further demonstrated that the confinement catalytic reaction at the gas-liquid interface between nitrogen gas and water microdroplets includes the production of ammonia and hydrogen peroxide.

[0048] In yet another embodiment of the present disclosure, step S4 involves collecting the generated ammonia gas or ammonia water. Specifically, the step of collecting the ammonia includes providing a collection device having a sealed collection chamber at the spray end of the microdroplet generator, such that the spray end is positioned within the collection chamber.

[0049] Furthermore, a conductive plate or heating device is provided within the collection chamber.

[0050] In one embodiment, a heating device is provided inside the collection chamber, and the heating device may be a device such as a heating tube or a heating plate. The heating temperature may be set to 35-50°C, and heating the collection chamber with the heating device contributes to the vaporization of ammonia and improves the ammonia production efficiency.

[0051] In another embodiment, a conductive plate is connected to the collection chamber, and the conductive plate is either grounded or connected to a high voltage to remove the charge accumulated in the collection chamber, avoid the formation of a high-capacitance capacitance system, suppress the formation of microdroplets based on electrohydrodynamics, and contribute to improving the Faraday efficiency of the microdroplet reaction. Specifically, if the microdroplet generation device is an electrospray device, the conductive plate may be connected to a high voltage of opposite polarity to the electrospray probe. The conductive plate may be, for example, a conductive polymer plate, which may be grounded or connected to a high voltage of opposite polarity to the microdroplet generation device. More preferably, the conductive polymer plate may be, for example, a high-density porous polyaniline laminate, and the thickness of the polyaniline plate may be 0.5 to 2 cm. By installing a conductive polymer plate, excess charge is removed to promote ammonia generation, while the conductive polymer plate receives the microdroplets to form a soft landing for the droplets, collects the regulating agent in the microdroplets, and enables the recycling of the regulating agent.

[0052] More preferably, in yet another embodiment, a conductive plate and a heating device may be provided simultaneously in the collection chamber. For example, by providing a heating device on the outer wall of the collection chamber, the conductive plate can not only remove the charge, but also heat the ammonia dissolved in the aqueous solution to vaporize it and accelerate the generation of ammonia.

[0053] Furthermore, in one embodiment of the present disclosure, a gas supply pipe is further connected to the collection chamber of the collection device, and a carrier gas (nitrogen gas) is supplied to the collection chamber via the gas supply pipe to drive the generated ammonia to be discharged through the gas discharge pipe.

[0054] Specifically, Figure 4 schematically shows the structure of a collection device 400 according to one embodiment of the present disclosure. As shown in Figure 4, the collection device 400 has a sealed collection chamber 410, and the electrospray probe 420 of a microdroplet generator (electrospray device) is inserted into the collection chamber 410. The collection chamber 410 can be made of, for example, a sealed box. The collection chamber 410 has a gas discharge pipe 412 provided on the upper right of the collection chamber 410 and a gas supply pipe 411 provided on the lower left of the collection chamber 410. Carrier gas is supplied via the gas supply pipe 411 to drive the gas to be discharged from the gas discharge pipe 412. A polyaniline laminate 430 that can assist in heating is installed inside the collection chamber 420. The polyaniline laminate 430 is provided below the electrospray probe 410 and is connected to a high voltage with opposite polarity to the electrospray probe 420.

[0055] The features and performance of this disclosure will be described in more detail below with reference to the examples.

[0056] Example 1 In the method for producing green ammonia according to this embodiment, the ammonia produced by the reaction of water and nitrogen gas in microdroplets is indirectly detected using the receiving device and mass spectrometer shown in Figure 3. Specifically, it is as follows:

[0057] (1) Prepare a 20 μmol / L fumaric acid aqueous solution, and use aqueous solution a as a 500 μg / mL HAuCl4 aqueous solution, aqueous solution b as a 500 μg / mL PdCl2 aqueous solution, aqueous solution c as a 500 μg / mL HAuCl4-PdCl2 aqueous solution, and aqueous solution d as a 10 -2 This was prepared as an aqueous solution of AuPd alloy NPs at a concentration of mg / mL.

[0058] (2) Aqueous solutions a to d were supplied to an air spray device to generate fine droplets. The inner diameter of the spray end of the inner tube of the air spray device was set to 150 μm, the syringe flow rate to 10 μL / min, and the outer tube diameter to 365 μm. Nitrogen gas was used as the sheath gas, and the sheath gas pressure was set to 60 psi.

[0059] Figure 5 shows the mass spectra of an aqueous solution of fumaric acid in negative and positive ion modes. The left side shows the mass spectrum in negative ion mode, and the right side shows the mass spectrum in positive ion mode. As can be seen from Figure 5, in negative ion mode, fumaric acid has an m / z of 114.9468 and a theoretical m / z of 115.0003, while in positive ion mode, it has an m / z of 115.0481. This is because fumaric acid belongs to the organic acid class and should not respond in positive ion mode. However, the mass spectral peak at m / z 115.0481 is an amide compound produced by the reaction of fumaric acid with ammonia, and because it contains a nitrogen atom, it exhibits a strong response in positive ion mode. As shown in Figure 6, in the positive ion mode, the fumaric acid aqueous solutions with added modifiers (aqueous solutions a-d) show not only the amidation reaction of the amino acid itself and that generated from nitrogen gas (m / z=115.0481), but also a difference of 34 between the mass spectral peak at m / z=149.0578 and the fumaric acid amidation mass spectral peak (m / z=115.0481). This indicates that two hydroxyl radicals (·OH) react simultaneously with fumaric acid in the microdroplet reaction. This result can also be observed in the negative ion mode, but the signal response is weak. Among the modifiers corresponding to aqueous solutions a-d, the AuPd alloy shows a high response, with its response value being 76% of the amidation product. These results indicate that nitrogen gas and water can produce ammonia through a microdroplet reaction, and that the yield of ammonia is related to the type of modifier.

[0060] Example 2 In the ammonia gas production method according to this embodiment, online mass spectrometry is performed using the mass spectrometer shown in Figure 3. Specifically, the procedure is as follows:

[0061] (1) Aqueous solutions were prepared as follows: Aqueous solution a was a 500 μg / mL HAuCl4 aqueous solution, Aqueous solution b was a 500 μg / mL PdCl2 aqueous solution, Aqueous solution c was a 500 g / mL HAuCl4-PdCl2 aqueous solution, and Aqueous solution d was a 50 μg / mL AuPd alloy NPs aqueous solution.

[0062] (2) Aqueous solutions a to d were supplied to the electrospray apparatus to generate fine droplets. Nitrogen gas was supplied to the spray end of the electrospray apparatus. The inner diameter of the electrospray probe was set to 50 μm, the flow rate of the syringe pump was set to 10 μL / min, and the electrospray bias voltage was set to -3 kV.

[0063] (3) Ammonia generated at the gas-liquid interface of the microdroplets was supplied to a mass spectrometer via a transport tube for online analysis.

[0064] As shown in Figure 7, the first spectrum on the left is the mass spectrum obtained from a microdroplet formed from pure water under an air atmosphere and is used as a negative control. The first spectrum on the right is the mass spectrum obtained from a microdroplet formed from pure water under a nitrogen gas atmosphere. These are the mass spectra of ammonia produced from aqueous solutions a-d and pure water (H2O) under an air atmosphere. As can be seen from Figure 7, with air as a control, only trace amounts of ammonia are detected in the microdroplets formed by pure water. For the microdroplets formed by aqueous solutions a-d, a characteristic ammonia peak is present at m / z 17. The abundance of ammonia produced increases significantly in gold-palladium alloy aqueous solutions compared to chlorauric acid, palladium chloride, and chlorauric acid-palladium chloride aqueous solutions.

[0065] Example 3 In the ammonia production method according to this embodiment, ammonia produced by the reaction of water and nitrogen gas in fine droplets is collected using the collection device shown in Figure 4. Specifically, it is as follows:

[0066] (1) Prepare aqueous solutions: Aqueous solution a is a 500 μg / mL HAuCl4 aqueous solution, aqueous solution b is a 500 μg / mL PdCl2 aqueous solution, aqueous solution c is a 500 μg / mL HAuCl4-PdCl2 aqueous solution, and aqueous solution d is a 10 -2 This was prepared as an aqueous solution of AuPd alloy NPs at a concentration of mg / mL.

[0067] (2) Aqueous solutions a to d were supplied to the electrospray apparatus to generate microdroplets. The inner diameter of the electrospray probe 420 of the electrospray apparatus was set to 50 μm, the flow rate of the syringe pump was set to 10 μL / min, and the electrospray bias voltage was set to -3 kV. The distance from the end of the electrospray probe 420 to the polyaniline laminate 430 below it was set to 3 cm.

[0068] (3) Nitrogen gas at a constant flow rate was supplied as a carrier gas to the lower left of the collection chamber 410, and the ammonia generated in the collection chamber 420 was discharged through the gas discharge pipe 412 in the upper right.

[0069] After spraying for 60 minutes, the collected ammonia was detected by gas chromatography. The ammonia generation capacity of nitrogen gas formed by aqueous solutions a-d and fine droplets of pure water is shown in Table 1 below.

[0070] [Table 1]

[0071] As can be seen from Table 1, the green ammonia production method of this disclosure significantly improves the amount of ammonia produced in the microdroplet reaction of nitrogen gas and water by adding different adjusting agents. The ammonia content in the microdroplets formed by pure water is extremely low and difficult to detect. A 500 μg / mL HAuCl4-PdCl2 (500 μg / mL) system can produce up to 74.3 mol / gh of ammonia, and 10 -2The mg / mL AuPd alloy system can produce up to 683.9 mmol / gh of ammonia, which is 9.2 times more than the chloraurate-palladium chloride system. It is highly practical, and from a green, environmentally friendly, and economic standpoint, it easily supports hydrogen gas production, providing a powerful solution to achieve the goal of "dual carbon."

[0072] The embodiments described above are only a selection of the embodiments of the Disclosure, not all embodiments. The detailed description of the embodiments of the Disclosure is not intended to limit the scope of the Disclosure for which protection is sought, and only selected embodiments of the Disclosure are shown. All other embodiments that a person skilled in the art could obtain without creative effort based on the embodiments of the Disclosure are all within the scope of the Disclosure.

Claims

1. Step S1 involves mixing water with one or more adjusting agents selected from nanomaterials, conductive polymers, and redox-active inorganic salts to obtain an aqueous solution. Step S2 involves supplying an aqueous solution to a microdroplet generating device to generate microdroplets with a size of 10 μm or less, By forming a nitrogen gas atmosphere at the spray end of the aforementioned minute droplets, the water and nitrogen gas in the minute droplets spontaneously undergo a radical reaction at the gas-liquid interface to produce ammonia, and the entire reaction equation is shown below in step S3. A method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, characterized by comprising step S4 of detecting or collecting the ammonia.

2. The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, as described in claim 1, characterized in that the microdroplet generating device is selected from an electrospray device, an air spray device, and an ultrasonic atomizing device.

3. The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, as described in claim 2, wherein the microdroplet generation device is an electrospray device, the electrospray device has an electrospray probe, the flow rate at which the aqueous solution is injected into the electrospray probe is 5 to 150 μL / min, the inner diameter of the electrospray probe is 5 to 150 μm, the applied bias voltage is 3 to 7 kV, thereby generating microdroplets of a size of less than 10 μm, and nitrogen gas is supplied to the spray end of the electrospray probe to form a nitrogen gas atmosphere.

4. The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, as described in claim 3, characterized in that the electrospray apparatus has a plurality of electrospray probes.

5. The method for producing green ammonia by a microdroplet reaction and a confinement catalytic reaction at the gas-liquid interface based on water and nitrogen gas, as described in claim 2, wherein the microdroplet generating device is an air spray device, the air spray device includes an inner tube and an outer tube fitted to the outside of the inner tube, a spray end is formed at the end of the inner tube, nitrogen gas is introduced into the outer tube as a sheath gas, the aqueous solution is injected into the inner tube and atomized by the sheath gas to form microdroplets, and the sheath gas flows to the spray end to form the nitrogen gas atmosphere.

6. The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, as described in claim 5, characterized in that the flow rate of the aqueous solution injected into the inner tube is 5 to 150 μL / min, the pressure of the nitrogen gas as the sheath gas is 60 to 120 psi, and the flight speed of the generated microdroplets is 65 to 110 m / s.

7. The inorganic salt is one or more selected from chlorauric acid, palladium chloride, and chlorauric acid-palladium chloride; the nanomaterial is one or more selected from gold nanoparticles, palladium-coated gold nanoparticles, gold-palladium nanocomposites, and magnetic nanoparticles; and the conductive polymer is C ６０ - (OH) ｎ The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, characterized in that the adjusting agent is one or more selected from alkalized polyaniline-gold nanoparticle composites and acidified polyaniline-gold nanoparticle composites, and the adjusting agent has an electron conduction promoting effect in the microdroplet reaction.

8. The step of detecting or collecting the ammonia is: The step of providing a mass spectrometer at the spray end of the microdroplet generating device to receive the product generated at the spray end and perform mass analysis, or The method for producing green ammonia by a microdroplet reaction based on water and nitrogen gas and a confinement catalytic reaction at the gas-liquid interface, characterized in that a collection device having a sealed collection chamber is provided at the spray end of the microdroplet generating device such that the spray end is positioned within the collection chamber, the product is ammonia or an amide, an organic acid is added to the aqueous solution in step S1, and the amide is produced by the reaction of the organic acid and ammonia, as described in claim 1.

9. The method for producing green ammonia by a microdroplet reaction and a confinement catalytic reaction at the gas-liquid interface based on water and nitrogen gas, characterized in that a conductive plate and / or heating device are further provided in the collection chamber, and the conductive plate is grounded or connected to a high voltage to remove the charge accumulated in the collection chamber.

10. The method for producing green ammonia by a microdroplet reaction and a confinement catalytic reaction at the gas-liquid interface based on water and nitrogen gas, characterized in that a gas supply pipe and a gas discharge pipe are connected to the collection chamber, nitrogen gas is introduced into the gas supply pipe, and the generated ammonia gas is discharged through the gas discharge pipe.

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