A method for hydrogen production based on microdroplets

Abstract

The present disclosure provides a kind of microdroplet-based hydrogen production method, it is related to green energy technology field.The hydrogen production method includes: water and adjusting agent are mixed, to obtain aqueous solution, wherein the adjusting agent is selected from one or more of nanomaterial, conductive polymer and inorganic salt with redox property;Aqueous solution is input into microdroplet generating device, to generate microdroplet, the size of the microdroplet is less than or equal to 10 μm, hydrogen radical is spontaneously generated by means of strong electric field in the gas-liquid interface double electric layer of microdroplet;The hydrogen radical is combined to generate hydrogen;The hydrogen or hydrogen radical is collected.By the strong electric field of microdroplet gas-liquid interface, the H + of water molecule in aqueous solution interface is obtained to form hydrogen radical, and two hydrogen radicals are combined to form hydrogen.The preparation process is simple, green and environmentally friendly, the added adjusting agent can effectively improve the yield of hydrogen, the preparation process is not limited by catalyst, and different production process requirements can be met.

Description

Technical Field

[0001] This disclosure relates to the field of green energy technology, and in particular to a method for preparing hydrogen based on microdroplets. Background Technology

[0002] Energy is one of the major problems facing human society today. Energy shortages, accompanied by energy crises, severely restrict the development of human society. The search for alternative green energy sources has become a research hotspot in the energy field. As a zero-carbon energy source, hydrogen energy has always received global attention. Hydrogen energy, with its high efficiency and cleanliness, is considered one of the most promising energy sources for the future. Hydrogen obtained by cracking water using renewable energy sources produces only water during combustion, achieving zero carbon dioxide emissions at the source, making it a truly green new energy source (green hydrogen). Exploring efficient methods and related processes for producing hydrogen through water cracking has become a research hotspot in the energy field.

[0003] Currently, hydrogen production technology mainly relies on photocatalysis to produce hydrogen. This process requires oxalic acid as a sacrificial agent, resulting in high production costs. Some technologies also involve photocatalytic fuel cell technology, utilizing the reverse principle of hydrogen fuel cells to directly separate hydrogen from water. This method uses an ion-exchange membrane to transfer protons or hydroxide ions; under light irradiation, hydrogen is generated at the cathode, and an oxidation reaction occurs at the anode to produce oxygen, achieving the goal of photocatalytic water splitting to produce hydrogen. However, this method suffers from drawbacks such as complex separation equipment and cost constraints due to catalyst limitations.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This disclosure provides a method for hydrogen preparation based on microdroplets, which solves the problems of high cost and complex equipment in the hydrogen preparation process.

[0006] This disclosure provides a method for preparing hydrogen based on microdroplets, including: S1, water and a regulator are mixed to obtain an aqueous solution, wherein the regulator is selected from one or more of nanomaterials, conductive polymers, and inorganic salts with redox properties; S2, an aqueous solution is input into a microdroplet generating device to generate microdroplets, the size of which is less than or equal to 10 μm, so that hydrogen free radicals are spontaneously generated at the gas-liquid interface of the microdroplets; S3, the hydrogen free radicals recombine to generate hydrogen gas; S4, collect the hydrogen gas or the hydrogen free radicals.

[0007] In one exemplary embodiment of this disclosure, the microdroplet generating device is selected from one of an electrospray device, a pneumatic spray device, and an ultrasonic atomizing device.

[0008] In one exemplary embodiment of this disclosure, the inorganic salt is selected from one or more of chloroauric acid, palladium chloride, and chloroauric acid-palladium chloride; the nanomaterial is selected from one or more of gold nanoparticles, palladium-coated gold nanoparticles, and gold-palladium nanocomposites; and the conductive polymer is selected from C 60 -(OH)n, one or more of the following: alkalized polyaniline-gold nanoparticle composite and acidified polyaniline-gold nanoparticle composite.

[0009] In one exemplary embodiment of this disclosure, when the regulator is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is 50~1000 μg / mL; when the regulator is a nanomaterial or a conductive polymer, the concentration of the nanomaterial or conductive polymer in the aqueous solution is 10 μg / mL. -5 ~10 -1 mg / mL.

[0010] In one exemplary embodiment of this disclosure, when the regulator is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is μg / mL.

[0011] In an exemplary embodiment of this disclosure, the microdroplet generating device is an electrospray device, the electrospray device has an electrospray probe, the flow rate of the aqueous solution injected into the electrospray probe is 5-150 μL / min; the inner diameter of the electrospray probe is 5-150 μm, and the applied bias voltage is 3-7 kV.

[0012] In one exemplary embodiment of this disclosure, the step of collecting the hydrogen gas includes: A receiving device is provided at the spray end of the microdroplet generating device. The receiving device has a sealed collection chamber and an outlet pipe communicating with the collection chamber. The spray end of the microdroplet generating device extends into the collection chamber so that the generated hydrogen gas enters the gas outlet pipe through the collection chamber.

[0013] In one exemplary embodiment of this disclosure, a refrigerant is provided outside the collection chamber to cool the water formed during the curing spray process; the refrigerant is selected from one or more of liquid nitrogen, ice water, ice-containing brine and ethylene glycol.

[0014] In one exemplary embodiment of this disclosure, a conductive polymer plate is disposed inside the collection chamber, and the conductive polymer plate is grounded or connected to a high voltage with a polarity opposite to that of the microdroplet generating device.

[0015] In one exemplary embodiment of this disclosure, the collection chamber is connected to an air inlet pipe, through which carrier gas is input to the collection chamber to drive the generated hydrogen gas to be output from the air outlet pipe.

[0016] In one exemplary embodiment of this disclosure, the step of collecting the hydrogen radicals includes: A free radical capture device is provided at the spray end of the microdroplet generating device, and the free radical capture device outputs large droplets composed of DMPO aqueous solution. A voltage of opposite polarity to that of the microdroplet generating device is applied to the output terminal of the free radical capturing device to cause the microdroplets to move toward the large droplet and capture the hydrogen free radicals generated by the microdroplets.

[0017] The beneficial effects of the hydrogen preparation method based on microdroplets in this disclosure are: The hydrogen preparation method disclosed herein produces microdroplets with a diameter of less than 10 μm using a microdroplet generation device. These microdroplets exhibit a "confined effect" at the interfacial scale, possessing unique physicochemical properties such as high specific surface area, abundant charge density, and a strong electric field within the dielectric double layer. As a microreactor, the microdroplets function based on the unique gas-liquid interface effect and the strong electric field of the dielectric double layer (10 μm). 7 V / cm), causing water molecules to ionize (H + ), forming hydrogen radicals (·H, H) + +e - →·H), further recombination occurs between ·H radicals (2·H→H2). However, due to the relatively short half-life of hydrogen radicals (·H) (<10), further recombination occurs between ·H radicals. -9 s), which will transiently reverse to form hydrogen ions (·He - →H + This process is controlled by electrons (e.g., electrons). - Whether electrons are transferred can be determined by modulating the electron transport properties of conductive metallic materials, nanomaterials, inorganic salts, etc., to determine whether electrons generated at the interface are transferred. - The hydrogen radicals (·H, H) are transferred to the forward direction of the reaction, causing the reaction to proceed in the forward direction. + +e - →·H) accumulates at the gas-liquid interface and recombines to generate hydrogen (H2), achieving efficient and spontaneous generation of hydrogen and providing a solution for green, efficient, and economical preparation of green hydrogen.

[0018] This hydrogen production method uses water as a raw material and significantly improves hydrogen production efficiency through the use of a regulator, achieving a hydrogen production efficiency of 113,400 μmol / gh. No catalyst is required, some of the regulator can be recycled, making it environmentally friendly and not limited by geographical location or integrated equipment. Production costs are controllable, and it can meet the needs of different process production.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a hydrogen preparation method based on microdroplets according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the structure of a microdroplet generation device and a free radical capture device according to an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the collection device and mass spectrometer according to another embodiment of the present disclosure; Figure 4 This is a schematic diagram of the structure of a collection device according to yet another embodiment of the present disclosure; Figure 5 EPR images of DMPO capturing hydrogen radicals in microdroplets formed from different aqueous solutions in Example 1 of this disclosure; Figure 6 The hydrogen gas chromatography-mass spectra are those of microdroplets generated by hydrogen production in different aqueous solutions in Example 2 of this disclosure. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] The following is a detailed description of the hydrogen preparation method based on microdroplets according to embodiments of this disclosure.

[0024] This disclosure provides a method for preparing hydrogen based on microdroplets, including: Step S1: Mix water and a regulator to obtain an aqueous solution, wherein the regulator is selected from one or more of metallic conductors, nanomaterials, conductive polymers, and inorganic salts with redox properties; Step S2: Input the aqueous solution into the microdroplet generating device to generate microdroplets. The size of the microdroplets is less than or equal to 10 μm, so as to spontaneously generate hydrogen free radicals at the gas-liquid interface of the microdroplets. Step S3, the hydrogen free radicals recombine to generate hydrogen gas; Step S4: Collect the hydrogen gas or the hydrogen free radicals.

[0025] This hydrogen production method introduces an electronic conductor into a microreactor using a specific regulator, selectively adjusting the dielectric bilayer thickness or conductivity to improve electron stripping efficiency and promote the interaction of hydrogen free radicals, thereby converting them into hydrogen.

[0026] In one embodiment of this disclosure, the inorganic salt is selected from one or more of chloroauric acid (HAuCl4), palladium chloride (PdCl2), and chloroauric acid-palladium chloride (HAuCl4-PdCl2). Through the redox effect of the above-mentioned inorganic salt, the gas-liquid interface properties of the microdroplets are improved, thereby increasing the hydrogen generation efficiency.

[0027] In one embodiment of this disclosure, the nanomaterial is selected from one or more of Au NPs, palladium-coated gold nanoparticles (Au@PdNPs), and gold-palladium alloy nanoparticles (AuPd alloy NPs); the conductive polymer is selected from C 60 One or more of the following nanoparticles are used: -(OH)n, alkalized polyaniline-gold nanoparticle composite (PANI@AuNPs-NaOH), and acidified polyaniline-gold nanoparticle composite (PANI@AuNPs-HCl). The addition of these nanoparticles enhances the interfacial effect, adjusts the dielectric bilayer thickness, alters the electron stripping efficiency, and promotes hydrogen generation.

[0028] Specifically, C 60 -(OH)n is C 60 Polyhydroxy compounds, also known as fullerols, are readily soluble in water due to the presence of multiple hydroxyl groups in their molecules. For example, they can be synthesized using amine catalysis. 60-(OH)n. ANI@AuNPs-NaOH and PANI@AuNPs-HCl can be prepared according to existing techniques. For example, in one embodiment, 3.5 mL of 55 nm gold nanoparticles are dispersed in 1.5 mL of 2 mM aniline and 0.25 mL of 40 mM SDS solution, vortexed for 1 min, and then 1.5 mL of 2 mM (NH4)2S2O8-HCl aqueous solution is added. The mixture is vortexed for 10 s and reacted at room temperature for 12 h. The aniline in the system polymerizes and coats the surface of the gold nanoparticles, forming a polymer-coated gold nanoparticle aqueous solution with a thickness of approximately 16 nm. After centrifugation and rinsing, PANI@AuNPs-HCl is obtained. PANI@AuNPs-HCl particles are then dispersed in an aqueous solution, 2 M NaOH solution is added, the pH of the solution is adjusted to 11.4, and the solution is magnetically stirred for 2 h to obtain PANI@AuNPs-NaOH.

[0029] In one embodiment of this disclosure, when the regulator is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is 50-1000 μg / mL; when the regulator is a nanomaterial or a conductive polymer, the concentration of the nanomaterial or conductive polymer in the aqueous solution is 10 μg / mL. -5 ~10 -1 mg / mL. Different concentrations of regulator resulted in different concentrations of hydrogen peroxide being generated in the reaction system.

[0030] Furthermore, in one embodiment of this disclosure, the regulator is HAuCl4, PdCl2, or HAuCl4-PdCl2, and the concentration of the regulator in the aqueous solution is 500 μg / mL. At this concentration, the hydrogen yield reaches 13200 μmol / gh or higher. Further, when the regulator is AuPd alloy NPs, the concentration of AuPd alloy NPs in the aqueous solution is 10... -2 At a concentration of mg / mL, the hydrogen yield reaches over 113,400 μmol / gh. Inorganic salts and nanoalloys differ in hydrogen production efficiency, with nanoalloys exhibiting superior hydrogen production capacity. This is partly due to the excellent electron stripping properties of nanoalloys, which promote the recombination of hydrogen radicals (·H), generating more hydrogen. On the other hand, inorganic salts act as sacrificial agents, and redox reactions exist between hydrogen radicals and the inorganic salt system (3·H + HAuCl4 → Au + 4HCl, 2·H + PdCl2 → Pd + 2HCl), which consume hydrogen radicals (·H).

[0031] In one embodiment of this disclosure, the microdroplet generating device is selected from an electrospray device, a pneumatic spray device, and an ultrasonic atomizing device. The specific construction of the electrospray device, pneumatic spray device, and ultrasonic atomizing device can be found in the prior art; for example, the specific construction of the electrospray device can be referred to the electrospray device in mass spectrometry analysis technology.

[0032] In one specific embodiment, the electrospray device may include a syringe, a connector, an electrospray probe, and a high-voltage power supply. The connector may be, for example, a two-way connector, through which the syringe and the electrospray probe are connected. The aqueous solution enters the electrospray probe through the syringe. A high-voltage electric field generates an electric field force at the spray tip of the electrospray probe, and the aqueous solution is atomized into microdroplets based on electrohydrodynamic principles.

[0033] In one specific embodiment, the pneumatic spray device may include a syringe, a three-way connector, a capillary tube, and a gas cylinder. The syringe and capillary tube are respectively connected to both ends of the three-way connector, and the other end of the three-way connector is connected to the gas cylinder to input sheath gas at different pressures. The output end of the capillary tube forms a spray probe. The aqueous solution enters the capillary tube through the syringe, and under the action of pneumatic atomization, microdroplets are formed at the tip of the probe.

[0034] In one specific embodiment, the ultrasonic atomizing device includes a syringe, an ultrasonic generator, and a spray head. The ultrasonic generator generates ultrasonic oscillation wave energy, and under the action of the ultrasonic oscillation wave energy, the aqueous solution is atomized into microdroplets.

[0035] In one embodiment of this disclosure, the microdroplet generation device is an electrospray device, which has an electrospray probe. The flow rate of the aqueous solution injected into the electrospray probe is 5-150 μL / min; the inner diameter of the electrospray probe is 5-150 μm, and the applied bias voltage is 3-7 kV. Further, the flow rate of the electrospray probe is 10 μL / min; the inner diameter of the electrospray probe is 50 μm. Under the above preparation parameters, the hydrogen generation rate can be increased.

[0036] In one embodiment of this disclosure, step S4, the step of collecting the hydrogen radicals, includes: A free radical capture device is provided at the spray end of the microdroplet generating device, and the output component of the free radical capture device is a large droplet containing a free radical scavenger. A voltage of opposite polarity to that of the microdroplet generating device is applied to the output terminal of the free radical capturing device to cause the microdroplets to move toward the large droplet and capture the hydrogen free radicals generated by the microdroplets.

[0037] Specifically, Figure 2 A schematic diagram of an apparatus for capturing hydrogen radicals according to one embodiment of this disclosure is shown. Please refer to... Figure 2The microdroplet generation device is an electrospray device, applying a negative high voltage to the electrospray probe 210. The free radical capture device has a large-diameter quartz capillary 220, through which a free radical capture agent is introduced via an injection pump (not shown), and a positive high voltage is applied to the quartz capillary 220 to form large droplets. Under the action of a strong electric field, the electrospray-formed microdroplets fly towards the surface of the high-speed rotating large droplets with opposite polarities formed by the soft landing of the droplets. The hydrogen free radicals (·H) formed in the system are captured by the free radical capture agent and collected.

[0038] Specifically, the free radical scavenger is a class of piperidine derivative light stabilizers with steric hindrance effects, such as salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines, etc. In this embodiment, the free radical scavenger is an aqueous solution of DMPO (5,5-dimethyl-1-pyrroline-N-oxide). Further, the inner diameter of the quartz capillary 220 is 140~300 μm to form larger droplets, facilitating the collection of hydrogen free radicals.

[0039] In one embodiment of this disclosure, step S4, the step of collecting the hydrogen gas, includes: A receiving device is provided at the spray end of the microdroplet generating device. The receiving device has a sealed collection chamber and an outlet pipe communicating with the collection chamber. The spray end of the microdroplet generating device extends into the collection chamber so that the generated hydrogen gas enters the gas outlet pipe through the collection chamber.

[0040] Furthermore, in one embodiment of this disclosure, a refrigerant is provided outside the collection chamber to cool and solidify the water formed during the spraying process; the refrigerant is selected from one or more of liquid nitrogen, ice water, ice-containing brine, and ethylene glycol. By providing a refrigerant, the hydrogen generation efficiency can be effectively promoted.

[0041] Specifically, Figure 3 This schematic diagram illustrates the structure of a receiving device in one embodiment of the present disclosure. Please refer to [link / reference]. Figure 3 The receiving device has a sealed collection chamber 320, into which the electrospray probe 310 of the microdroplet generating device (electrospray device) extends. The collection chamber 320 can be constructed, for example, using a round-bottom flask. The collection chamber 320 has an outlet pipe 321 for discharging hydrogen gas from the chamber. The collection chamber 320 is placed within a cooling chamber 330, which is filled with a refrigerant (e.g., liquid nitrogen) to form a cold trap system for cooling and solidifying the water formed during the spraying process.

[0042] Furthermore, in one embodiment of this disclosure, the hydrogen generated by the electrospray probe 310 in the collection chamber 320 enters the transmission pipeline 340 through the outlet pipeline 321. The hydrogen is then input into the mass spectrometer 350 through the transmission pipeline 340 for online mass spectrometry detection and analysis.

[0043] In one embodiment of this disclosure, a conductive polymer plate is provided within the collection chamber of the collecting device. The conductive polymer plate is grounded or connected to a high voltage with a polarity opposite to that of the microdroplet generating device. Specifically, the conductive polymer plate can be, for example, a dense, porous polyaniline plate with a thickness of 0.5–2 cm. By providing the conductive polymer plate, excess charge is removed to promote hydrogen generation, and the microdroplets are received to facilitate soft landing and collection of the regulator within the microdroplets, thus enabling the recycling of the regulator.

[0044] In one embodiment of this disclosure, the collection chamber of the collecting device is further connected to an inlet pipe, through which carrier gas is input to the collection chamber to drive the generated hydrogen gas out through the outlet pipe. Specifically, the carrier gas may be, for example, hydrogen, nitrogen, or a mixture of both.

[0045] Specifically, Figure 4 This schematic diagram illustrates the structure of a receiving device in another embodiment of the present disclosure. Please refer to [link / reference]. Figure 4 The receiving device has a sealed collection chamber 420, into which the electrospray probe 410 of the microdroplet generating device (electrospray device) extends. The collection chamber 420 can be, for example, constructed as a sealed enclosure. The collection chamber 420 has an outlet pipe 421 and an inlet pipe 422. The outlet pipe 421 is located at the upper right of the collection chamber 420, and the inlet pipe 422 is located at the lower left of the collection chamber 420. Carrier gas is input through the inlet pipe 422, driving the gas to exit from the outlet pipe 421. A polyaniline plate 430 is installed inside the collection chamber 420, positioned below the electrospray probe 410, and connected to a high voltage with the opposite polarity to that of the electrospray probe 410.

[0046] The features and performance of this disclosure will be further described in detail below with reference to embodiments.

[0047] Example 1

[0048] This embodiment provides a method for preparing hydrogen, through... Figure 2 The microdroplet generation device and free radical capture device shown are used to collect hydrogen free radicals. Details are as follows: (1) Prepare aqueous solutions, wherein aqueous solution a is an aqueous solution of HAuCl4 with a concentration of 50 μg / mL; aqueous solution b is an aqueous solution of PdCl2 with a concentration of 50 μg / mL; aqueous solution c is an aqueous solution of HAuCl4-PdCl2 with a concentration of 50 μg / mL; and aqueous solution d is an aqueous solution of AuPd alloy NPs with a concentration of 5 μg / mL.

[0049] (2) The reaction solutions a~d are respectively fed into the microdroplet generating device to generate microdroplets. The inner diameter of the electrospray probe of the microdroplet generating device is 50 μm, the flow rate of the injection pump is 10 μL / min, and the electrospray bias voltage is -6.3 kV.

[0050] (3) A DMPO solution with a concentration of 200 μg / mL was injected into the quartz capillary 220 of the free radical capture device to generate large droplets. At the same time, the inner diameter of the quartz capillary 220 was 150 μm, the flow rate of the injection pump was 10 μL / min, and the applied bias voltage was +3kV.

[0051] (4) The negatively charged microdroplets fly toward the high-speed rotating positively charged large droplets, and the hydrogen free radicals (·H) formed in the system are captured and collected by DMPO.

[0052] like Figure 5 The image shows the electron paramagnetic resonance (EPR) spectra of hydrogen radicals (·H) generated from aqueous solutions a~d and pure water (H2O) after being captured by DMPO. Figure 5 It can be seen that in the range of 3320-3420, there are 5 characteristic peaks of the DMPO-H adduct formed by the capture of hydroxyl radicals (·OH) by DMPO, characterized by g iso =2.0057, a iso ( 14 N) = 1.64 mT(×1) and a iso ( 1 H) = 2.25 mT (×2). In the EPR spectrum, four characteristic peaks are observed simultaneously, indicating that reactive oxygen species (·OH and ·OOH) are captured by DMPO to form DMPO-H adducts. These peaks are characterized by g iso = 2.0057, a iso ( 14 N) = 1.48 mT(×1) anda iso ( 1 H) = 1.48 mT (×1). For microdroplets formed from pure water, the corresponding characteristic peak is relatively weak.

[0053] Example 2

[0054] This embodiment provides a method for preparing hydrogen, and through methods such as... Figure 3 The mass spectrometer 350 shown is used for online mass spectrometry analysis. Details are as follows: (1) Prepare aqueous solutions, wherein aqueous solution a is an aqueous solution of HAuCl4 with a concentration of 500 μg / mL; aqueous solution b is an aqueous solution of PdCl2 with a concentration of 500 μg / mL; aqueous solution c is an aqueous solution of HAuCl4-PdCl2 with a concentration of 500 μg / mL; and aqueous solution d is an aqueous solution of AuPd alloy NPs with a concentration of 50 μg / mL.

[0055] (2) The reaction solutions a~d are respectively fed into the microdroplet generating device to generate microdroplets. The inner diameter of the electrospray probe of the microdroplet generating device is 50 μm, the flow rate of the injection pump is 10 μL / min, and the electrospray bias voltage is -3 kV.

[0056] (3) The hydrogen generated at the gas-liquid interface of the microdroplets enters the mass spectrometer 350 through the transmission pipe 340 for online detection and analysis.

[0057] like Figure 6 The image shows the hydrogen gas chromatography-mass spectra of hydrogen radicals (·H) generated from aqueous solutions a~d and pure water (H2O). From... Figure 6 It can be seen that, using air as a control, no hydrogen gas was detected in the microdroplets formed from pure water. The microdroplets formed from aqueous solutions a~d exhibited a characteristic hydrogen peak at m / z 2. Compared to aqueous solutions of chloroauric acid, palladium chloride, and chloroauric acid-palladium chloride, the hydrogen abundance generated by the gold-palladium alloy aqueous solution was significantly enhanced.

[0058] Example 3

[0059] This embodiment provides a method for preparing hydrogen, and through methods such as... Figure 4 The collection device shown collects hydrogen gas. Details are as follows: (1) Prepare aqueous solutions, wherein 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 g / mL HAuCl4-PdCl2 aqueous solution; and aqueous solution d is a 10 g / mL PdCl2 aqueous solution. -2 An aqueous solution of AuPd alloy NPs at a concentration of mg / mL.

[0060] (2) Aqueous solutions a~d are respectively fed into the microdroplet generating device to generate microdroplets. The inner diameter of the electrospray probe 410 of the microdroplet generating device is 50 μm, the flow rate of the injection pump is 10 μL / min, and the electrospray bias voltage is -3 kV. The distance between the end of the electrospray probe 410 and the polyaniline plate 430 below is 3 cm.

[0061] (3) Nitrogen gas with a certain flow rate is introduced into the lower left of the collection chamber 420 as a carrier gas, and the hydrogen gas in the collection chamber 420 is carried out through the gas outlet pipe 421 in the upper right.

[0062] After 60 minutes of spraying, the collected hydrogen gas was analyzed. The mass spectrometry results were consistent with the hydrogen peak intensity results in Example 2. The hydrogen production capacity of the microdroplets formed by aqueous solutions a~d is shown in Table 1 below.

[0063] Table 1

[0064] As shown in Table 1, the hydrogen preparation method disclosed in this paper significantly increases the hydrogen production by adding different modifiers. The hydrogen content in the microdroplets formed from pure water is extremely low and difficult to detect. The inorganic salt chloroauric acid-palladium chloride (500 μg / mL) system can produce a maximum of 19200 μmol / gh, while 10 -2 The AuPd alloy system with a capacity of mg / mL can produce up to 113,400 μmol / gh, which is 5.9 times that of the chloroauric acid-palladium chloride system. It is highly practical and can provide support for hydrogen generation from the perspective of green environmental protection and economic conservation, providing a powerful solution for achieving the "dual carbon" goal.

[0065] The embodiments described above are some, but not all, of the embodiments of this disclosure. The detailed description of the embodiments of this disclosure is not intended to limit the scope of the claimed disclosure, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

Claims

1. A method for preparing hydrogen based on microdroplets, characterized in that, include: S1, water and a regulator are mixed to obtain an aqueous solution, wherein the regulator is selected from one or more of nanomaterials, conductive polymers, and inorganic salts with redox properties; S2, an aqueous solution is input into a microdroplet generating device to generate microdroplets, the size of which is less than or equal to 10 μm, so that hydrogen free radicals are spontaneously generated at the gas-liquid interface of the microdroplets; S3, the hydrogen free radicals recombine to generate hydrogen gas; S4, collect the hydrogen gas or the hydrogen free radicals; The inorganic salt is selected from one or more of chloroauric acid, palladium chloride, and chloroauric acid-palladium chloride; the nanomaterial is selected from one or more of gold nanoparticles, palladium-coated gold nanoparticles, and gold-palladium nanocomposites; the conductive polymer is selected from C 60 -(OH)n, one or more of the following: alkalized polyaniline-gold nanoparticle composite and acidified polyaniline-gold nanoparticle composite.

2. The method for preparing hydrogen based on microdroplets according to claim 1, characterized in that, The microdroplet generating device is selected from one of the following: an electro-spraying device, a pneumatic spraying device, and an ultrasonic atomizing device.

3. The method for preparing hydrogen based on microdroplets according to claim 1, characterized in that, When the regulator is an inorganic salt, the concentration of the inorganic salt in the aqueous solution is 50~1000 μg / mL; when the regulator is a nanomaterial or a conductive polymer, the concentration of the nanomaterial or conductive polymer in the aqueous solution is 10 μg / mL. -5 ~10 -1 mg / mL.

4. The method for preparing hydrogen based on microdroplets according to claim 1, characterized in that, The microdroplet generation device is an electrospray device, which has an electrospray probe. The flow rate of the aqueous solution injected into the electrospray probe is 5-150 μL / min. The inner diameter of the electrospray probe is 5-150 μm, and the applied bias voltage is 3-7 kV.

5. The method for preparing hydrogen based on microdroplets according to claim 1, characterized in that, The steps for collecting the hydrogen gas include: A receiving device is provided at the spray end of the microdroplet generating device. The receiving device has a sealed collection chamber and an outlet pipe communicating with the collection chamber. The spray end of the microdroplet generating device extends into the collection chamber so that the generated hydrogen gas enters the gas outlet pipe through the collection chamber.

6. The method for preparing hydrogen based on microdroplets according to claim 5, characterized in that, The outside of the collection chamber is equipped with a refrigerant to cool and solidify the water formed during the spraying process; the refrigerant is selected from one or more of liquid nitrogen, ice water, ice-containing brine and ethylene glycol.

7. The method for preparing hydrogen based on microdroplets according to claim 5, characterized in that, A conductive polymer plate is provided inside the collection chamber. The conductive polymer plate is grounded or connected to a high voltage with the opposite polarity to the microdroplet generating device.

8. The method for preparing hydrogen based on microdroplets according to claim 5, characterized in that, The collection chamber is connected to an air inlet pipe, through which carrier gas is input to the collection chamber, so as to drive the generated hydrogen gas to be output from the air outlet pipe.

9. The method for preparing hydrogen based on microdroplets according to claim 1, characterized in that, The steps for collecting the hydrogen radicals include: A free radical capture device is provided at the spray end of the microdroplet generating device, and the free radical capture device outputs large droplets composed of DMPO aqueous solution. A voltage of opposite polarity to that of the microdroplet generating device is applied to the output terminal of the free radical capturing device to cause the microdroplets to move toward the large droplet and capture the hydrogen free radicals generated by the microdroplets.

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