Proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures and preparation method thereof

Abstract

The invention discloses a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperature 300-500 DEG C and a preparation method thereof, and belongs to the technical field of hydrogen separation membrane materials. The electrochemical hydrogen pump is of a sandwich structure, the middle layer is a compact proton conductive ceramic BZCYYbF layer, the upper layer is an Ag-3% Pd layer, and the lower layer is a NiO-BZCYYbF composite material layer of a porous structure. The proton conductivity and stability of the BZCYYb material under medium and low temperature application conditions are improved by adopting an anion F doping mode. The preparation method comprises the following steps: firstly, preparing a NiO-BZCYYbF support body by adopting a traditional dry pressing method, and then preparing electrolyte slurry; a NiO-BZCYYbF supporting body biscuit is coated with a BZCYYbF electrolyte layer through a dip-coating method, then the temperature is increased to 1400-1450 DEG C, sintering is carried out for 5-6 h, a half cell is obtained, finally, the surface of electrolyte is coated with Ag-3% Pd slurry, further sintering is carried out, and the porous NiO-BZCYYbF compact BZCYYbF porous Ag-3% Pd asymmetric ceramic sample of a sandwich structure is obtained. The method is simple and efficient in process, and the obtained proton conductor ceramic electrochemical hydrogen pump is excellent in hydrogen separation performance at medium and low temperatures.

Description

Technical Field

[0001] The present invention belongs to the technical field of separation membrane materials, and particularly relates to a proton-conducting ceramic electrochemical hydrogen pump applicable to medium and low temperatures of 300-500 °C, a preparation method thereof, and an application of the proton-conducting ceramic electrochemical hydrogen pump for hydrogen separation. Background Art

[0002] Hydrogen energy, known as the "ultimate energy" with the most promising application prospects in the 21st century, will play an irreplaceable key role in helping the decarbonization of the existing energy system due to its unique advantages such as wide sources, high combustion calorific value, high energy conversion efficiency, and pollution-free products. In the current membrane separation technology for hydrogen, the all-solid-state proton-conducting membrane based on the atomic sieving mechanism has a selectivity for H 2 that can reach 100%, and has unique advantages in the preparation of high-purity H 2 . However, most current proton-conducting ceramic membranes for H 2 separation need to operate at high temperatures (600-1000 °C). However, at the current stage, the low-temperature section of the relevant industrial processes involved in upstream H 2 production, such as water-gas shift, is carried out at temperatures below 450 °C, and the operating temperature of downstream H 2 applications such as proton exchange membrane fuel cells is (<600 °C). Therefore, there is a serious temperature mismatch problem between the H 2 separation process at high temperatures and the production and application of H 2 at medium and low temperatures, accompanied by huge energy consumption, which severely restricts its industrial development.

[0003] Therefore, it is urgent for us to develop a proton-conducting ceramic membrane that can operate at medium temperatures (300-500 °C) to meet the requirements of hydrogen separation and purification.

[0004] In membrane separation technology, compared with metal membranes, porous membranes, polymer membranes, etc., dense ceramic hydrogen permeable membranes have the advantages of higher hydrogen selectivity, better chemical stability, lower production costs, and wider application fields, and have already been regarded as a class of competitors with great development and application potential in H 2 separation membranes. Currently, among dense ceramic hydrogen permeable membranes, strontium cerate (SrCeO 3 ), barium cerate (BaCeO 3 ), barium zirconate (BaZrO 3 ) series materials doped with multivalent ions have been the most widely studied, and these materials usually have high proton conductivity at high temperatures. However, when the temperature drops to medium temperature, the membrane materials have insufficient original H 2 separation driving force due to the rapid decline of electron conductivity and proton conductivity. Therefore, in order to effectively improve hydrogen permeability, an auxiliary external circuit can be added to enhance the chemical potential difference on both sides of the membrane so as to improve H2 Driving force for separation. This electrochemical method based on membrane separation technology is also known as the electrochemical hydrogen pump method. Since 1980, Sedlak et al. have first verified the feasibility of the electrochemical hydrogen pump technology in H 2 separation and purification, and then this technology has been widely concerned. The electrochemical hydrogen pump based on inorganic proton conductor membranes has become a current research hotspot because of its low economic cost, extremely high H 2 purity, and the ability to integrate separation and reaction coupling.

[0005] US20230151500A1 discloses a novel electrocatalytic membrane reactor and uses it in the preparation of high-purity hydrogen. The electrocatalytic membrane reactor uses an H-shaped electrolytic cell. In this tank, the cathode chamber is separated from the anode chamber by a diaphragm. The membrane electrode is used as the anode, and the auxiliary electrode is used as the cathode. A direct current-regulated power supply supplies a constant current, and the flow of the reaction solution is achieved by a pump. In the disclosure, the electrocatalytic and membrane separation functions are combined, and an organic electrochemical reaction is used to replace the organic electrochemical oxidation reaction in the anode chamber to reduce the overpotential of the oxygen evolution reaction and carry out a hydrogen reaction in the hydrogen evolution reaction. High-purity hydrogen is prepared in the cathode chamber. This technology can improve the efficiency of the reactor, but still uses electrolysis as a means of preparing hydrogen.

[0006] US6168705B1 discloses an electrochemical gas purifier system composed of a battery module and an accessory assembly and installed in a frame. The module consists of many single cells, and each cell can purify and finally produce hydrogen at a pressure exceeding 2000 psi. The method includes introducing a contaminated hydrogen stream into a cell containing an anode and a cathode, with an electrolyte membrane placed therebetween. Hydrogen is oxidized at the anode into electrons that electrochemically migrate through the membrane to protons at the cathode, where they recombine with electrons from an external power supply. The contaminants leave the anode side of the cell, while the purified hydrogen leaves the cathode side of the cell. This method uses noble metals as the substrate electrodes, with a high cost. Summary of the Invention

[0007] To solve the disadvantages and deficiencies of the prior art, the primary object of the present invention is to propose a proton conductor hydrogen-permeable membrane material with high hydrogen permeability and high stability for use in an electrochemical hydrogen pump. Specifically, the present invention provides a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures of 300 - 500 °C, its preparation method, and applications.

[0008] In the first aspect, the present application provides a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures. The proton conductor ceramic electrochemical hydrogen pump has a "sandwich" structure, and the "sandwich" structure is divided into an upper layer, a middle layer, and a lower layer.

[0009] Further, the intermediate layer is a dense proton-conducting ceramic BZCYYbF layer, the upper layer is an Ag-3%Pd layer, and the lower layer is a NiO-BZCYYbF composite material layer with a porous structure. The medium and low temperature is 300-500 °C.

[0010] Further, the BZCYYbF material is: BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ F x (BZCYYb1711F x ) or BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ F x (BZCYYb4411F x ), where δ is a non-stoichiometric ratio and 0 < x ≤ 0.2.

[0011] Further, the BZCYYbF material is prepared by the following method: Prepare the BZCYYbF material by using the EDTA-citric acid mixed complex method, and the EDTA-citric acid mixed complex method includes the following steps.

[0012] (1) Weigh Ba(NO 3 ) 2 , Zr(NO 3 ) 4 ·5H 2 O, Ce(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O, Yb(NO 3 ) 3 ·5H 2 O nitrates and NH 4 F salt, add deionized water, and dissolve to obtain a mixed salt solution; Further, in step (1), the dissolution of the salts is accelerated by magnetic stirring to obtain a mixed salt solution.

[0013] (2) Add EDTA and citric acid to the mixed salt solution obtained in step (1), where the molar ratio of EDTA, citric acid to the total metal ions in the mixed salt solution is 1:1.5:1; (3) Add an alkaline non-metal compound to the mixed solution and adjust the pH value of the mixed solution to 8-10; (4) Stir and evaporate the mixed solution obtained in step (3) at 90-150 °C to obtain a wet gel; (5) Calcinate the wet gel obtained in step (4) at 300-600 °C to obtain a precursor powder; (6) Sinter the precursor powder obtained in step (5) at 1050-1150 °C for 5-10 h to obtain a phase-formed powder.

[0014] Further, the alkaline non-metal compound in step (3) is ammonia water.

[0015] Further, the stirring and evaporation time in step (4) is 4-6 h.

[0016] Further, the heating and cooling rate during sintering in step (6) is 3-5 °C / min.

[0017] Further, in step (1), Ba(NO 3 ) 2 , Zr(NO 3 ) 4 ·5H 2 O, Ce(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O, Yb(NO 3 ) 3 ·5H 2 O nitrates and NH 4 F salts are in a metering ratio of: 10:1:7:1:1:x or 10:4:4:1:1:x, where (x = 1 / 2 / 3 / 4).

[0018] Further, the amount of deionized water used in step (1) is 200-300 mL.

[0019] Further, in step (6), a muffle furnace is used for high-temperature sintering.

[0020] In a second aspect, the present invention provides a method for preparing a proton-conducting ceramic electrochemical hydrogen pump suitable for medium and low temperatures, comprising the following steps: (1) Prepare a NiO-BZCYYbF support: (1-1) Mix BZCYYbF with NiO powder and soluble starch in a mass ratio of 4:6:2, add ethanol or acetone, ball mill, and dry to obtain a porous matrix precursor; Further, in the step (1-1), the ball milling time is 12-24 h, the drying temperature is selected to be 100-150 °C, and the drying time is 2-10 h.

[0021] (1-2) Press the porous matrix precursor obtained in the step (1-1) into a mold to obtain a green film sheet; Further, the pressing is carried out in a stainless steel mold, and the pressing pressure is 5-10 MPa; (1-3) Sinter the green film sheet at 800-1000 °C for 4-5 h to obtain a support substrate of an anion F-doped asymmetric membrane; (2) Prepare a porous NiO-BZCYYbF||dense BZCYYbF half-cell: (2-1) Mix BZCYYbF, binder, and ethanol evenly at a weight ratio of 4:1:40 to prepare a BZCYYbF 0.1 dip-coating slurry; Further, in the step (2-1), the binder is terpineol containing 6 wt.% ethyl cellulose.

[0022] (2-2) Dip-coat the slurry prepared in the step (2-1) on the support substrate of the anion F-doped asymmetric membrane, and wait for the dip-coating solution to dry at room temperature; (2-3) Sinter the green film sheet at 1300-1500 °C for 10-20 h to obtain a porous NiO-BZCYYbF||dense BZCYYbF half-cell; Further, in the step (2-3), a high-temperature muffle furnace is used for sintering.

[0023] (3) Coat the half-cell prepared in the step (2) with Ag-3%Pd paste and further sinter it to obtain an electrochemical ceramic hydrogen pump with a "sandwich" structure of porous NiO-BZCYYbF||dense BZCYYbF||porous Ag-3%Pd.

[0024] Further, the heating and cooling rate during sintering in the step (1-3) is 1-2 °C / min, and the heating and cooling rate during sintering in the step (2-3) is 1-2 °C / min.

[0025] In a third aspect, the present invention provides an application, in which a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures prepared by the method of the first aspect or the second aspect is used to separate hydrogen from a hydrogen-containing mixed system H 2 / He, H 2 / N 2 , and H 2 / CH 4 selected. At 400 °C, applying a maximum current density of 300 mA cm-2 At this time, a hydrogen permeation rate of 2.24 mL min -1 cm -2 and a Faraday efficiency close to 100% were achieved, and continuous operation could be carried out for up to 300 hours without obvious performance degradation.

[0026] Compared with the prior art, the present invention has the following advantages: The present invention uses an anion F-doped proton-conducting ceramic BZCYYbF material. An electrode support with a porous NiO-BZCYYbF structure is obtained by dry pressing, and then a BZCYYbF electrolyte green body is obtained by dip coating. Then, an electrochemical ceramic hydrogen pump with a "sandwich" structure of porous NiO-BZCYYbF||dense BZCYYbF||porous Ag-3%Pd is obtained through a bonding technique.

[0027] The present invention uses dry pressing to prepare NiO-BZCYYbF with a porous structure. This NiO-BZCYYbF layer serves both as a support layer to provide mechanical strength for the entire ceramic sample and as an electrode material to promote the dissociation and association processes of hydrogen molecules on the membrane surface. The relatively thin dense BZCYYbF electrolyte layer reduces the bulk diffusion resistance. At the same time, the doping of anion F reduces the valence electron density of O, thereby weakening the metal-O bond and increasing the oxygen vacancy concentration of the membrane material, thus increasing the hydrogen permeation flux. Compared with the proton conductor membranes reported in the current literature, this electrochemical ceramic hydrogen pump can increase the hydrogen permeation rate to more than 5 times, showing great superiority in hydrogen permeation performance. The preparation process of the present invention is simple and easy to operate. The prepared proton ceramic hydrogen pump has the advantages of low internal resistance and small electrode concentration polarization, and can obtain excellent hydrogen separation and purification effects. Description of the Drawings

[0028] Figure 1 X-ray diffraction patterns of ceramic samples BZCYYb1711Fx (x = 0 / 0.05 / 0.1 / 0.2) prepared in Example 1 and the comparative example; Figure 2 For the electrochemical ceramic hydrogen pump "porous NiO-BZCYYb1711F 0.1 ||dense BZCYYb1711F 0.1 ||porous Ag-3%Pd" prepared in Example 1, scanning electron microscope images of the reduced surface (a) and cross-section (b); Figure 3 Conductivity performance diagrams of ceramic samples BZCYYb1711Fx (x = 0 / 0.05 / 0.1 / 0.2) prepared in Example 1 and the comparative example; Figure 4Hydrogen permeation curves of the electrochemical ceramic hydrogen pumps of Example 1 and Comparative Example 1, and hydrogen permeation curves of the electrochemical ceramic hydrogen pumps of Example 2 and Comparative Example 2; Figure 5 XRD pattern of BZCYYb1711F of Example 1 0.1 after long-term stability testing; Figure 6 SEM micrograph of the electrochemical ceramic hydrogen pump of Example 1 after long-term stability hydrogen permeation performance testing in a mixed atmosphere containing H 2 . Detailed implementation mode

[0029] The technical solution of the present invention will be further described below in conjunction with specific examples. The raw materials used in the following examples can be obtained from conventional commercial channels unless otherwise specified; the processes used, unless otherwise specified, are conventional processes in the art. Example 1

[0030] This example is carried out according to the following steps: A preparation method of a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures, comprising the following steps: (1) BZCYYb1711F 0.1 Material preparation: (1-1) Measure 26.134 g of Ba(NO 3 ) 2 , 4.2932 g of Zr(NO 3 ) 4 ·5H 2 O, 30.3954 g of Ce(NO 3 ) 3 ·6H 2 O, 3.8302 g of Y(NO 3 ) 3 ·6H 2 O, 4.4914 g of Yb(NO 3 ) 3 ·5H 2 O nitrates and 0.3704 g of NH 4 F, add 300 mL of deionized water, and mix evenly; then weigh 57.636 g of citric acid monohydrate and 58.448 g of EDTA and add them to the above-mentioned obtained mixed solution, and then add ammonia water to adjust the pH value of the mixed solution to 8. After obtaining a clear solution, stir and evaporate at 95 °C at a rotation speed of 100 r / min for 6 h to obtain a wet gel.

[0031] (1-2) Transfer the wet gel to an evaporating dish, heat it with an electric furnace to 600 °C until the gel self-ignites to obtain a precursor powder; then place the precursor powder in a high-temperature muffle furnace and heat it to 1050 °C at a heating rate of 2 °C / min, hold for 10 h, and then cool it to room temperature at a rate of 5 °C / min to obtain a phase-formed powder.

[0032] (2)NiO - BZCYYb1711F 0.1 Preparation of an anode support: (2-1)Weigh 4.0 g of BZCYYb1711F 0.1 phase-formed powder, 6.0 g of NiO, and 2.0 g of soluble starch. After preliminary mixing, add 25 mL of ethanol and ball-mill at a rotation speed of 350 r / min. Take it out after 24 h and dry it naturally; (2-2)After slightly grinding the powder obtained in step (2-1), weigh 0.6 g of the powder and place it in a cylindrical stainless-steel mold with an inner diameter of 16 mm. Keep it under a pressure of 8 MPa for 30 s to obtain a green film.

[0033] (2-3)Place the green film obtained by pressing and forming in a high-temperature muffle furnace for sintering. The sintering process is to heat from room temperature to 800 °C at a rate of 2 °C / min, hold for 4 h, and then cool to room temperature at a cooling rate of 2 °C / min to obtain an anode support with a certain mechanical strength.

[0034] (3)Porous NiO - BZCYYb1711F 0.1 || Dense BZCYYb1711F 0.1 Preparation of a half-cell: (3-1)Mix 8 g of BZCYYb1711F 0.1 (containing 1% NiO)powder, 2 g of terpineol (containing 6 wt.% ethyl cellulose), and 80 g of ethanol evenly to prepare a BZCYYb1711F 0.1 dip-coating slurry.

[0035] (3-2)Subsequently, dip-coat the prepared slurry on the porous anode support 20 times, each time for 30 s. After the dip-coating liquid dries naturally at room temperature for 1 h, place it in a high-temperature muffle furnace and calcine it at 1450 °C, hold for 5 h, and the heating and cooling rate is 2 °C / min to obtain a porous NiO - BZCYYb1711F 0.1 || Dense BZCYYb1711F 0.1 half-cell.

[0036] (4) Coat the half-cell prepared in step (3-2) with Ag-3%Pd paste, and after further sintering, a porous NiO-BZCYYb1711F with a "sandwich" structure is obtained. 0.1 || Dense BZCYYb1711F 0.1 || Electrochemical ceramic hydrogen pump with porous Ag-3%Pd.

[0037] Perform phase analysis on the obtained BZCYYb1711F 0.1 membrane, and the results are as Figure 1 shown. After doping with fluorine, the material maintains its original cubic phase structure and no other impurity phases are formed.

[0038] (5) The scanning electron microscope images of the surface and cross-section of the BZCYYb1711F 0.1 asymmetric membrane are as shown in Figure 2 a and b. From Figure 2 a, it can be seen that the grains on the surface of the BZCYYb1711F 0.1 membrane after doping with fluorine are closely packed and the grain boundaries are clearly distinguishable, indicating that the grains are well-developed. From Figure 2 b, the cross-section of the asymmetric membrane can be observed. It can be seen that there are no bubbles or through-holes inside the electrolyte, and gas cannot directly penetrate through the lattice inside the membrane, which indicates that the BZCYYb1711F 0.1 membrane sintered at 1450 °C is dense. At the same time, it can be seen that the anode support layer has a relatively high porosity, which can provide a transmission path for hydrogen diffusion. Example 2

[0039] A preparation method of a proton conductor ceramic electrochemical hydrogen pump, comprising the following steps: (1) Preparation of BZCYYb4411F 0.1 material: (1-1) Measure 26.134 g of Ba(NO 3 ) 2 , 17.1728 g of Zr(NO 3 ) 4 ·5H 2 O, 17.3688 g of Ce(NO 3 ) 3 ·6H 2 O, 3.8302 g of Y(NO 3 ) 3 ·6H 2 O, 4.4914 g of Yb(NO 3 ) 3 ·5H 2 O nitrates and 0.3704 g of NH 4F, 300 mL of deionized water was added and mixed evenly; then 57.636 g of citric acid monohydrate and 58.448 g of EDTA were weighed and added to the above-mentioned obtained mixed solution, and then ammonia water was added to adjust the pH value of the mixed solution to 8. After obtaining a clear solution, it was stirred and evaporated at 95 °C at a rotation speed of 100 r / min for 6 h to obtain a wet gel.

[0040] (1-2) The wet gel was transferred to an evaporating dish and heated with an electric furnace to 600 °C until the gel self-combusted to obtain a precursor powder; the precursor powder was then placed in a high-temperature muffle furnace and heated to 1150 °C at a heating rate of 2 °C / min and held for 10 h, and then cooled to room temperature at a rate of 5 °C / min to obtain a phase-formed powder.

[0041] (2) Replace the "BZCYYb1711F 0.1 powder" in steps (2) and (3) of Example 1 with "BZCYYb4411F 0.1 ", and the other required raw materials, reagents and preparation methods are the same as those in Example 1. Finally, a porous NiO-BZCYYb4411F 0.1 || dense BZCYYb4411F 0.1 || ceramic sample of porous Ag-3%Pd was obtained. Comparative Example 1

[0042] (1) Replace the mass of NH 0.1 F in the "BZCYYb1711F 4 powder" in step (1) of Example 1 with 0 g, 0.1854 g, 0.7415 g, and the corresponding doping amounts are x = 0, 0.05, 0.2. The XRD images of the corresponding materials were tested, as Figure 1 shown, indicating the influence of F doping on the crystal structure. Furthermore, the direct current four-probe method was used to test the conductivity of the samples to observe the influence of F doping on its proton conductivity, as Figure 3 shown.

[0043] (2) Further, the phase-formed powder BZCYYb1711F 0 with an F doping amount of 0 was selected, and steps (2) and (3) in Example 1 were continued. Finally, a porous NiO-BZCYYb1711F 0 || dense BZCYYb1711F 0 || ceramic sample of porous Ag-3%Pd was obtained. Then its hydrogen permeation performance was tested and compared with the BZCYYb1711F 0.1 electrochemical ceramic hydrogen pump, as Figure 4 shown in Figures 4a and 4b. Comparative Example 2

[0044] (1) Replace the mass of NH in the "BZCYYb4411F powder" in step (1) of Example 2 with 0 g to synthesize the phase-forming powder BZCYYb4411F with an F doping amount of 0. 0.1 F 4 and obtain the phase-forming powder BZCYYb4411F with an F doping amount of 0. 0 .

[0045] (2) Further, select the phase-forming powder BZCYYb4411F with an F doping amount of 0, and continue according to steps (2) and (3) in Example 2 to finally obtain the porous NiO-BZCYYb4411F with a "sandwich" structure. 0 ||Dense BZCYYb4411F 0 ||Porous Ag-3%Pd ceramic sample. Then conduct hydrogen permeability performance testing on it and compare it with the BZCYYb4411F 0 electrochemical ceramic hydrogen pump, as shown in 0.1 Figures 4c and 4d. Figure 4 .

[0046] Performance Testing (1) Conductivity Testing Conduct conductivity performance testing on the proton conductor hydrogen permeable membrane materials obtained in Example 1 and the comparative example. The testing method is as follows: Apply silver paste on both sides of the prepared ceramic membrane sheet, and at the same time cover it with silver wire current collectors. Dry it in an oven at 120 °C for 2 h to fix it. Seal the test membrane sheet on the corundum tube through ceramic sealant, connect it to the electrochemical workstation through silver wires, and conduct testing using a programmed temperature tube furnace. Repeat the testing in the way of first cooling and then heating. Except for a holding time of 40 min at 600 °C, the holding time at other test points is 30 min. Apply a constant voltage U = 0.5 V to the two electrodes through the electrochemical workstation, and record the current I passing through the sample during the holding process. Then obtain the electrode area A according to the width × height of the sample membrane sheet, and substitute the previously recorded membrane thickness L into the formula to obtain the conductivity calculation result of the sample.

[0047] (2) Hydrogen Permeability Conduct performance testing on the proton conductor hydrogen permeable membrane materials obtained in Example 1 and 2 and the comparative example. The testing method is as follows: After the diaphragm is collected by silver wire and silver paste, the sheet-shaped membrane is sealed at one end of the corundum tube with a sealant, and then a quartz glass tube is sleeved outside the corundum tube for feeding. Wait for 24 h until the sealant is completely dry, and then fix the device in a tube furnace. The airtightness of the device is tested by the pressure-holding method. If there is no air leakage in the device, the temperature can be raised to cure the sealant. The temperature-rising program required for curing the sealant is set as follows: first, raise the temperature from room temperature to 80 °C at a rate of 1 °C / min, then keep it at 80 °C for 2 h, and then continue to raise the temperature to 150 °C at a rate of 1 °C / min and keep it at 150 °C for 2 h. After curing, raise the temperature to the required test temperature (500 °C, 450 °C, 400 °C, 350 °C, 300 °C) at a rate of 1 °C / min, and keep it at each test temperature for 120 minutes for testing. The flow rate of the gas used for testing is precisely controlled by a mass flow controller. A hydrogen-helium mixed gas with a volume ratio of 1:1 is introduced on the feed side, and its flow rate is 80 mL / min. Argon with a flow rate of 80 mL / min is used as the purge gas, and the purge tail gas is introduced into an Agilent 7890A gas chromatograph for hydrogen content analysis. The flow rate of the tail gas is measured with a soap bubble flowmeter.

[0048] The hydrogen permeation performance of various diaphragms is as Figure 4 shown. Compared with the undoped 1711F 0 and 4411F 0 diaphragms in Comparative Example 1 and Comparative Example 2, under the same test conditions, the hydrogen permeation amounts of the 1711F 0.1 diaphragm and 4411F 0.1 diaphragm in Example 1 and Example 2 have been significantly improved, indicating that the BZCYYbF 0 diaphragm doped with fluorine elements has good hydrogen permeability.

[0049] (3) Stability The BZCYYb1711F 2 diaphragm whose hydrogen permeation performance has been tested for 300 h in an atmosphere of 400 °C, 50 vol% H 2 -50 vol% He (50 vol% N 4 / 50 vol% CH 0.1 ) is observed for the XRD pattern, and as Figure 6 shown, the microscopic morphology remains basically unchanged after testing, indicating that the BZCYYb1711F 0.1 diaphragm has good chemical stability.

[0050] In summary, the proton electrochemical ceramic hydrogen pump provided by the present invention has both excellent hydrogen separation efficiency and chemical stability, has a high hydrogen permeation rate, and has good stability. Therefore, it can be applied to the hydrogen separation in hydrogen-containing mixed gases or applied to the production of hydrogen-related membrane reactors.

[0051] The above embodiments are only preferred exemplary embodiments of the present application, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can easily think of development or replacement, which all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures, characterized in that: The proton conductor ceramic electrochemical hydrogen pump has a "sandwich" structure, which is divided into an upper layer, a middle layer and a lower layer. The middle layer is a dense proton conductive ceramic BZCYYbF layer, the upper layer is an Ag-3% Pd layer, and the lower layer is a NiO-BZCYYbF composite material layer with a porous structure. The medium and low temperature is 300-500°C.

2. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 1, characterized in that: The BZCYYbF material is: BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ F x (BZCYYb1711F x ) or BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ F x (BZCYYb4411F x ), where δ is a non-stoichiometric ratio, 0<x≤0.

2.

3. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to any one of claims 1-2, characterized in that: The BZCYYbF material is prepared by the following method: (1) According to a fixed molar ratio of 10:1:7:1:1:x or 10:4:4:1:1:x, where x = 1, 2, 3 or 4; weigh Ba(NO3)2, Zr(NO3)4·5H2O, Ce(NO3)3·6H2O, Y(NO3)3·6H2O, Yb(NO3)3·5H2O nitrates and NH4F salts, add deionized water, and dissolve to obtain a mixed salt solution; (2) adding EDTA and citric acid to the mixed salt solution obtained in step (1), wherein the molar ratio of EDTA to citric acid to the total metal ions in the mixed salt solution is 1:1.5:1; (3) adding an alkaline non-metallic compound to the mixed solution to adjust the pH value of the mixed solution to 8 to 10; (4) stirring and evaporating the mixed solution obtained in step (3) at 90 to 150° C. to obtain a wet gel; (5) calcining the wet gel obtained in step (4) at 300-600°C to obtain a precursor powder; (6) Sinter the precursor powder obtained in step (5) at 1050-1150°C for 5-10 h to obtain a phase powder.

4. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 3, characterized in that: The alkaline non-metallic compound in step (3) is aqueous ammonia.

5. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 3, characterized in that: The stirring evaporation time in step (4) is 4 to 6 hours.

6. A proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 3, characterized in that: The heating and cooling rate during sintering in step (6) is 3 to 5 °C / min.

7. A method for preparing a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to any one of claims 1 to 6, characterized in that The steps include: (1) Preparation of NiO-BZCYYbF support: (1-1) BZCYYbF is mixed with NiO powder and soluble starch in a mass ratio of 4:6:2, ethanol or acetone is added, ball milling is performed, and drying is performed to obtain a porous matrix precursor; (1-2) pressing the porous matrix precursor powder obtained in step (1-1) into a shape to obtain a membrane embryo; (1-3) sintering the membrane green body at 800-1000 °C for 4-5 h to obtain a supporting substrate for the anion F-doped asymmetric membrane; (2) Preparation of porous NiO-BZCYYbF||dense BZCYYbF half-cell: (2-1) BZCYYbF, a binder, and ethanol were mixed uniformly at a weight ratio of 4:1:40 to prepare BZCYYbF 0.1 Dipping slurry; (2-2) dip-coating the slurry prepared in step (2-1) on the supporting substrate of the anion F-doped asymmetric membrane, and allowing the dip-coated solution to dry at room temperature; (2-3) Sintering the green membrane at 1300-1500 °C for 10-20 h to obtain a porous NiO-BZCYYbF||dense BZCYYbF half-cell; (3) The half-cell prepared in step (2) is coated with Ag-3%Pd slurry and further sintered to obtain a "sandwich" structure of porous NiO-BZCYYbF||dense BZCYYbF||porous Ag-3%Pd electrochemical ceramic hydrogen pump.

8. The method for preparing a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 7, characterized in that: The heating rate during sintering in step (1-3) is 1 to 2 °C / min, and the heating rate during sintering in step (2-3) is 1 to 2 °C / min.

9. The method for preparing a proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures according to claim 7, characterized in that: In step (2-1), the binder is pinene alcohol containing 6 wt% ethyl cellulose.

10. An application, characterized in that: The proton conductor ceramic electrochemical hydrogen pump suitable for medium and low temperatures as described in any one of claims 1 to 6 is used to selectively separate hydrogen from a hydrogen-containing mixed gas.

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