An electrochemical synthesizer for in-situ hydrogenation of CO2 and its preparation method and application

Abstract

The present invention relates to an electrochemical synthesizer for in-situ hydrogenation of CO2, and its preparation method and application. The electrochemical synthesizer for in-situ hydrogenation of CO2 comprises: an air electrode support tube having a hollow structure and closed at one end; an electrolyte layer arranged on the outer surface of the air electrode support tube; a fuel electrode layer arranged on the electrolyte layer near the closed end area; a catalyst layer arranged on the electrolyte layer near the open end area; and a hydrogen permeable membrane arranged on the electrolyte layer and used to isolate the fuel electrode layer and the catalyst layer. According to the present invention, a simple battery structure can be used to make CO2 react with H2 produced by high-temperature electrolysis of water at a suitable temperature to produce products such as CO, CH4 or CH3OH in situ, avoiding the problems of storage and transportation of H2 and high-temperature decomposition of products such as CH4 or CH3OH, and the process of hydrogen production by electrolysis of water is green and pollution-free.

Description

Technical Field

[0001] The present invention belongs to the technical field of renewable energy and CO2 recycling, and particularly relates to an electrochemical reaction synthesizer for in-situ hydrogenation conversion of CO2 and a method thereof. Background Art

[0002] Against the backdrop of the severe global greenhouse effect, it is urgent to convert and recycle large amounts of CO2 in a clean manner. As a carbon resource, CO2 can be converted into high-value-added fuels and chemicals such as CO, CH4, and CH3OH by reacting with H2, making it a very promising carbon conversion method.

[0003] Currently, there is extensive research on the reaction of CO2 and H2 to produce high-value-added hydrocarbon products, but most of this research focuses on catalyst materials, the use of industrially produced H2 and CO2 for the reaction, and reactor design. For example, patent US09745235B2 discloses a method for producing syngas by introducing carbon dioxide and hydrogen into a metal reactor. Hydrogen production and CO2 hydrogenation in separate reactors not only complicate the system but also lead to high costs and efficiency losses. Furthermore, since the majority of hydrogen currently produced in my country comes from gray hydrogen produced by fossil fuels, carbon emissions are unavoidable.

[0004] Proton conducting Solid Oxide Electrolysis Cell (PC-SOEC) is an electrochemical device that operates at medium to high temperatures (400-750°C) and efficiently converts renewable electricity into "green hydrogen" through proton conduction. In PC-SOEC, water vapor is electrolyzed on the anode side (Formula 1), and protons migrate to the cathode through the electrolyte to generate H2 (Formula 2); if CO2 is introduced into the fuel electrode side, in-situ hydrogenation of CO2 can be achieved, and the generation of products such as CO, CH4 and CH3OH can be controlled (Formulas 3-5), thereby achieving efficient in-situ conversion of CO2. High-temperature electrolysis has high efficiency and low power consumption, and CO2 is more active and has a lower energy barrier required for conversion. At the same time, the cell structure can be used to flexibly arrange catalysts and regulate the reaction temperature to improve the reaction efficiency, conversion rate and product selectivity of CO2 conversion.

[0005] H2O→2H + +1 / 2O2+2e- (1);

[0006] 2H + +2e - →H2 (2);

[0007] CO2+H2→CO+H2O (3);

[0008] CO2+4H2→CH4+2H2O (4);

[0009] CO2+3H2→CH3OH+H2O (5).

[0010] Currently, there are reports of methods using flat-plate proton conductor solid oxide electrolysis cells to electrolyze water to produce hydrogen and react with CO2 in situ. However, the operating temperature of water electrolysis to produce hydrogen is generally high (750-600°C). In this temperature range, the CO2 conversion product is single (mainly CO), which cannot achieve efficient preparation of high value-added products (CH4, CH3OH, etc.). At the same time, its compressive strength is not high enough, which is not conducive to subsequent synthesis reactions. Summary of the Invention

[0011] Problems to be solved by the invention:

[0012] In response to the above problems, the purpose of the present invention is to provide an electrochemical reaction synthesizer for in-situ hydrogenation conversion of CO2 and its preparation method, as well as a method for achieving efficient and selective conversion of CO2 by utilizing the electrode layout structure combined with the temperature gradient.

[0013] To this end, the present invention provides an electrochemical synthesizer for in-situ hydrogenation conversion of CO2, comprising:

[0014] An air electrode support tube having a hollow structure and closed at one end;

[0015] an electrolyte layer disposed on the outer surface of the air electrode support tube;

[0016] a fuel electrode layer disposed on the electrolyte layer near the closed end region;

[0017] a catalyst layer disposed on the electrolyte layer near one end of the opening;

[0018] A hydrogen permeable membrane is provided on the electrolyte layer and is used to isolate the fuel electrode layer and the catalyst layer.

[0019] In the present disclosure, the electrochemical reactor for in-situ hydrogenation of CO2 is based on a tubular air electrode supported PC-SOEC, which uses renewable electricity to electrolyze water vapor in a high temperature range (750-600°C) to directly react hydrogen with CO2 in a low temperature range (500-300°C) to produce high value-added fuels and chemicals. According to the present invention, a simple cell structure can be used to react CO2 with H2 produced by high-temperature electrolysis of water at a suitable temperature to produce products such as CO, CH4 or CH3OH in situ, avoiding the problems of storage and transportation of H2 and high-temperature decomposition of products such as CH4 or CH3OH, and the process of hydrogen production by electrolysis of water is green and pollution-free.

[0020] Preferably, the material of the air electrode support tube includes a proton conductor material and an active material; the thickness of the air electrode support tube is 0.5 to 1.5 mm;

[0021] The proton conductor material is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0≤x≤0.8, 0≤y≤0.2, and M is at least one of Cu, Y, In, Yb, and Sc; preferably, the proton conductor material is BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC);

[0022] The active material is selected from La 1-a Sr a Co 1-b Fe b O3, La 1-c Sr c MnO3、LaNi 1-d Fe d O3, La 2-e Sr e At least one of NiO4, wherein 0≤a≤1, 0≤b≤1, 0≤c≤0.5, 0≤d≤1, and 0≤e≤1.

[0023] Furthermore, preferably, the mass ratio of the proton conductor material to the active material is 7 / 3 to 3 / 7.

[0024] Preferably, the electrolyte layer is a proton conductor material, and the proton conductor material is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0≤x≤0.8, 0≤y≤0.2, and M is at least one of Cu, Y, In, Yb, and Sc; preferably, the proton conductor material is BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC);

[0025] The thickness of the electrolyte layer is 5 to 50 μm.

[0026] Preferably, the material of the catalyst layer includes Ru, Pd, In2O3, Ir, CeO2, ZnO-ZrO2, FeO z (one or more oxides of Fe, including ferrous oxide, ferric oxide, ferrous oxide, etc.), NiO, CuO, CeO2, (La 0.75 Sr 0.25 ) 0.9 (Cr 0.5 Mn 0.5 ) 0.9 (Ni f Cu 1-f ) 0.1 O 3-δ (LSCM-NiCu, 0≤f≤1), La2NiO4, M / NO (M is at least one of Fe, Co, Ni, Cu, Mo, Rh, Ir, Pd, Pt, Ag, Au, Na, K, Cs, NO is at least one of Al2O3, SiO2, CeO2, TiO2, ZrO2, ZnO, MgO) and a proton conductor material. The proton conductor material is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0≤x≤0.8, 0≤y≤0.2, and M is at least one of Cu, Y, In, Yb, and Sc; preferably, the proton conductor material is BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC);

[0027] The content of the proton conductor material in the catalyst layer is 10 to 60 wt%;

[0028] The thickness of the catalyst layer is 5 to 50 μm.

[0029] Preferably, the fuel electrode layer is a hydrogen electrode layer;

[0030] The fuel electrode layer is made of NiO and a proton conductor material;

[0031] The mass fraction of NiO in the fuel electrode layer is between 30% and 70%;

[0032] The thickness of the fuel electrode layer is 5 to 50 μm.

[0033] Preferably, the hydrogen permeable membrane is annular;

[0034] The hydrogen permeable membrane composition is selected from Pd, BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0≤x≤0.8, 0≤y≤0.2, and M is at least one of Cu, Y, In, Yb, and Sc; preferably, the hydrogen permeable membrane is composed of BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC);

[0035] The hydrogen permeable membrane has a width (radial direction of the synthesizer) of 0.5 to 2 cm and a thickness (axial direction of the synthesizer) of 0.2 to 1.5 mm.

[0036] Preferably, the electrolyte layer completely covers the outer surface of the air electrode support tube;

[0037] The width of the fuel electrode layer is less than the distance from the left side of the hydrogen permeable membrane to the closed end;

[0038] The width of the catalyst layer is less than the distance from the right side of the hydrogen permeable membrane to one end of the opening.

[0039] Preferably, the electrochemical synthesizer for in-situ hydrogenation conversion of CO2 also includes a first heating device and a second heating device, preferably including a first heating device that places the fuel electrode layer in a high-temperature heating zone of 750 to 600°C and a second heating device that places the catalyst layer in a medium-temperature heating zone of 500 to 300°C.

[0040] Preferably, the second heating device is provided with a CO2 introduction pipe.

[0041] On the other hand, the present invention provides a method for preparing CO, methane or methanol by electrochemical reaction, characterized in that, using the above-mentioned electrochemical synthesizer for in-situ hydrogenation conversion of CO2, when the electrochemical synthesizer is in operation, the fuel electrode layer (for example, the hydrogen electrode layer) is controlled to be in a high-temperature heating zone of 750 to 600°C, and the catalyst layer is controlled to be in a medium-temperature heating zone of 500 to 300°C, and water vapor is electrolyzed by electric energy to produce hydrogen, which reacts with CO2 in situ to produce CO, methane or methanol.

[0042] In another aspect, the present invention provides a method for preparing the above-mentioned electrochemical synthesizer for in-situ hydrogenation of CO2, comprising:

[0043] (1) preparing an air electrode layer as a support tube blank, and then calcining it to obtain an air electrode support tube;

[0044] (2) preparing an electrolyte layer on the outer surface of the air electrode support tube, and then sintering it to obtain a half-cell;

[0045] (3) preparing a fuel electrode layer and a catalyst layer on the surface of the obtained half-cell, respectively, and then calcining them twice;

[0046] (4) preparing a circular hydrogen permeable membrane ceramic sheet and sealing it to the electrolyte surface between the hydrogen electrode layer and the catalyst layer;

[0047] (5) Connecting wires and assembling to obtain the electrochemical synthesizer for in-situ hydrogenation conversion of CO2.

[0048] Preferably, in step (1), the proton conductor material powder and the active material powder are mixed and then subjected to isostatic pressing or casting to prepare a support tube blank;

[0049] The calcination temperature is 600-1300° C., and the calcination time is 1-4 hours.

[0050] Preferably, it is characterized in that in step (2), after the proton conductor material powder is prepared into an electrolyte layer slurry, the slurry is evenly coated on the outer surface of the air electrode support tube by dipping, screen printing or spraying and dried; the sintering temperature is 900-1400°C and the time is 2-5 hours.

[0051] Preferably, in step (3), Ru, Pd, In2O3, Ir, CeO2, ZnO-ZrO2, FeO z (one or more oxides of Fe), NiO, CuO, CeO2, (La 0.75 Sr 0.25 ) 0.9 (Cr 0.5 Mn 0.5 ) 0.9 (Ni f Cu 1-f ) 0.1 O 3-δ A catalyst layer slurry is prepared from at least one of (LSCM-NiCu, 0≤f≤1), La2NiO4, M / NO (M is at least one of Fe, Co, Ni, Cu, Mo, Rh, Ir, Pd, Pt, Ag, Au, Na, K, and Cs, and NO is at least one of Al2O3, SiO2, CeO2, TiO2, ZrO2, ZnO, and MgO) and proton conductor material powder; after NiO powder and proton conductor material powder are prepared into fuel electrode slurry, the fuel electrode layer slurry and the catalyst layer slurry are uniformly coated on the outer surface of the electrolyte layer by impregnation, screen printing, or spraying, and dried; the temperature of the secondary calcination is 900-1400°C, and the time is 1-4 hours.

[0052] Preferably, in step (4), Pd powder, BaCe 1-x-y Zr x M y O3 powder, Ca 0.9 In 0.1 At least one of ZrO3 powder and LaNbO3 powder is mixed, and is molded by isostatic pressing or casting to prepare a circular ceramic sheet blank, which is then sintered at 900-1500° C. for 2-5 hours to obtain the hydrogen permeable membrane.

[0053] Beneficial effects of the present invention:

[0054] The present invention has a simple structure and only requires a small amount of humid air and CO2 during the reaction. It can achieve the process from water electrolysis to CO2 hydrogenation on a single device, and regulate the CO2 hydrogenation conversion rate and selectivity according to the temperature gradient. At the same time, the humid air and CO2 hydrogenation products are in different chambers, which is conducive to product separation. The battery structure supported by the air electrode allows the fuel electrode and CO2 reaction zone to be located outside the tube, making it easier to design different catalysts and layout the temperature gradient. The present invention utilizes the proton conductivity characteristics of the proton conductor material and the good thermal shock resistance of the tubular battery to construct an electrochemical synthesizer within a large temperature range (300-750°C). The fuel electrode in the higher temperature range electrolyzes water vapor to produce hydrogen. After the hydrogen passes through the hydrogen permeable membrane, it reacts in situ with CO2 in the lower temperature range to produce fuels such as CO, methane or methanol. The electrochemical synthesizer device includes a tubular battery tube made of a proton conductor oxide material, which is composed of an air electrode, an electrolyte layer, a hydrogen electrode layer, a catalyst layer, a hydrogen permeable membrane and electrode leads. Compared with the CO2 hydrogenation conversion reactor and Fischer-Tropsch reactor commonly used in the chemical industry, this method has a simple device, fewer steps, and only requires the consumption of renewable electricity. It has the advantages of being cleaner, more environmentally friendly, and more energy efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Schematic diagram of the structure of a temperature gradient CO2 in-situ hydrogenation electrochemical reactor according to an embodiment of the present invention, wherein: 1 - air electrode support tube (referred to as air electrode tube); 2 - electrolyte layer; 3 - fuel electrode layer; 4 - catalyst layer; 5 - high temperature heater; 6 - medium temperature heater; 7 - CO2 inlet tube; 8 - terminal drainage; 9 - hydrogen permeable membrane;

[0056] Figure 2 This is a physical diagram of a temperature gradient CO2 in-situ hydrogenation electrochemical reactor according to an embodiment of the present invention;

[0057] Figure 3 yes Figure 2 Gas chromatography analysis results of the fuel-side tail gas during operation of the CO2 in-situ hydrogenation electrochemical reactor. DETAILED DESCRIPTION

[0058] The present invention is further described below through the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, rather than to limit the present invention.

[0059] Disclosed herein is a CO2 in-situ hydrogenation electrochemical reactor (hereinafter referred to as "electrochemical reactor") that integrates water electrolysis to produce hydrogen and CO2 hydrogenation conversion. Figure 1 1 is a schematic structural diagram of an electrochemical reactor according to an embodiment of the present invention; Figure 2 This is a physical diagram of a temperature gradient CO2 in-situ hydrogenation electrochemical reactor according to an embodiment of the present invention; Figure 3 yes Figure 2 Gas chromatography analysis results of the fuel-side tail gas during operation of the CO2 in-situ hydrogenation electrochemical reactor.

[0060] The electrochemical reactor of the present invention utilizes electrical energy to efficiently electrolyze water vapor to produce dry pure hydrogen, which reacts with CO2 in situ to produce high-value-added fuels and chemicals. Specifically, the electrochemical properties of proton conductor materials are utilized to electrolyze water vapor at the anode and generate hydrogen at the cathode within a medium- to high-temperature range (600-750°C). This hydrogen is then purged with an inert gas to a relatively low-temperature catalytic zone (<500°C) where it directly reacts with CO2 to produce products such as CO and CH4 in situ. The electrochemical reactor is primarily based on a proton conductor solid oxide electrolysis cell supported by a tubular air electrode.

[0061] like Figure 1 As shown, the electrochemical reactor is tubular and includes an air electrode tube 1, an electrolyte layer 2 arranged outside the air electrode tube 1, a fuel electrode layer 3 arranged outside the electrolyte layer 2, a catalyst layer 4, a high-temperature heater 5, a medium-temperature heater 6 and a hydrogen permeable membrane 9, etc.

[0062] [Air electrode tube]

[0063] In the present invention, the air electrode tube 1 is used to support the strength of the electrochemical reactor and decompose water vapor to produce oxygen and protons. It is preferably composed of a proton conductor material and an active material to form an air electrode tube of a certain length. Among them, the active material is La 1- c Sr c MnO3(LSM, 0≤c≤0.5), La 1-a Sr a Co 1-b Fe b O3 (LSCF, 0≤a≤1, 0≤b≤1), LaNi 1-d Fe d O3 (LNF, 0≤d≤1) or La 2-e Sr eNiO4 (LSN, 0≤e≤1), etc. The proton conductor electrolyte material is preferably BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC), BaCe 0.8-x Zr x Y 0.2 O 3-δ (BCZY, 0.1≤x≤0.8, y=0.2), BaCe 0.8-x Zr x Y 0.1 Yb 0.1 O 3-δ (BCZYYb, 0.1≤x≤0.8, y=0.2) or BaZr x Y y O 3-δ (BZY, 0.1≤y≤0.5, x+y=1). The air electrode tube 1 can be made into a tubular support tube blank by isostatic pressing or casting, and then the support tube blank is calcined into a support tube. For example, the air electrode tube is formed by isostatic pressing or casting, and the support tube is obtained after calcining at 900-1000℃ for 2-5 hours. The thickness of the air electrode tube is preferably 0.5-1.0 mm, more preferably 0.6-0.8 mm. As a pre-step for CO2 conversion, water vapor is electrolyzed here to produce oxygen and protons. In the present invention, the air electrode layer 1 is made of a mixed material of at least one of LSM, LSCF, LNF or LSN as an active material and a proton conductor material. The typical composition can be exemplified by La 1.2 Sr 0.8 NiO4-BaCe 0.68 Zr 0.1 Y 0.2 Yb 0.1 Cu 0.02 O 3-δ (ie, LSN-BCZYYC). The active material is electronically conductive and can catalyze electrochemical reactions.

[0064] The air electrode tube 1, serving as a support tube, is formed as an internally hollow tube with one end open and the other closed. The air electrode tube 1 is hollow inside, and an electrolyte layer 2 is formed on its outer surface. The air electrode tube is formed as a cylindrical hollow tube with one end open and the other closed. Wires extend from the air electrode tube and the fuel electrode layer to connect to both ends of the renewable power source.

[0065] [Electrolyte layer]

[0066] In the present invention, the electrolyte layer 2 is made of a proton conductor material and is located in the middle layer of the electrochemical device, mainly used for conducting protons. The proton conductor electrolyte material is preferably BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC), BaCe 0.8- x Zr x Y 0.2 O 3-δ (BCZY, 0.1≤x≤0.8, y=0.2), BaCe 0.8-x Zr x Y 0.1 Yb 0.1 O 3-δ (BCZYYb, 0.1≤x≤0.8, y=0.2) or BaZr x Y y O 3-δ At least one of (BZY, 0.1≤y≤0.5, x+y=1). Typical compositions include BaCe 0.68 Zr 0.1 Y 0.2 Yb 0.1 Cu 0.02 O 3-δ .

[0067] The electrolyte layer 2 can be prepared by impregnation, deposition, or other processes, and can have a thickness of 10-30 μm. Furthermore, the length of the electrolyte layer 2 is equal to the total length of the support tube. As an example, a proton conductor electrolyte material is prepared into a slurry, uniformly coated on the outer surface of the air electrode tube, dried, and sintered at 1000-1300°C for 2-5 hours to produce the electrolyte layer.

[0068] [Fuel electrode layer]

[0069] The fuel electrode layer 3 is located at the outermost side of the electrochemical device and is mainly used to connect the negative electrode of the battery and the generation of hydrogen. Protons are reduced to hydrogen by electrons here. In the present invention, the fuel electrode layer 3 is made of a mixture of NiO and a proton conductor material. The proton conductor material is preferably BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC), BaCe 0.8-x Zr x Y 0.2 O 3-δ(BCZY, 0.1≤x≤0.8, y=0.2), BaCe 0.8-x Zr x Y 0.1 Yb 0.1 O 3-δ (BCZYYb, 0.1≤x≤0.8, y=0.2) or BaZr x Y y O 3-δ At least one of (BZY, 0.1≤y≤0.5, x+y=1). Typical compositions include NiO-BaZr 0.8 Y 0.2 O3.

[0070] The fuel electrode layer 3 can be prepared by processes such as dipping, screen printing, and spraying, and its thickness can be 15-30 μm. Furthermore, the length of the fuel electrode layer 3 should be shorter than the length of the electrolyte layer 2, and the catalyst layer 4 is prepared on the remaining surface of the electrolyte layer 2. As an example, the fuel electrode layer is prepared by evenly coating the outer surface of the electrolyte layer with fuel electrode slurry, drying it, and sintering it at 1000-1300°C for 2-5 hours.

[0071] [Catalyst layer]

[0072] The catalyst layer 4 is also located at the outermost side of the electrochemical device, similar to the fuel electrode layer 3, and is located on the surface of the electrolyte layer 2, mainly used to catalyze the reaction of CO2 and H2. In the present invention, the catalyst layer is composed of Ru, Pd, In2O3, Ir, CeO2, ZnO-ZrO2, FeO z (one or more oxides of Fe), NiO, CuO, CeO2, (La 0.75 Sr 0.25 ) 0.9 (Cr 0.5 Mn 0.5 ) 0.9 (Ni x Cu 1-x ) 0.1 O 3-δAt least one of (LSCM-NiCu, 0≤x≤1), La2NiO4, M / NO (M is at least one of Fe, Co, Ni, Cu, Mo, Rh, Ir, Pd, Pt, Ag, Au, Na, K, Cs, and NO is at least one of Al2O3, SiO2, CeO2, TiO2, ZrO2, ZnO, and MgO) and a proton conductor material. For example, catalyst layer 4 can be a pure catalyst such as LSCM-NiCu, CeO2, etc., or a mixture of a catalyst and a proton conductor material for synergistically catalyzing CO2 conversion. Preferably, the length of the electrolyte layer is equal to the total length of the air electrode tube, and the sum of the lengths of the fuel electrode layer and catalyst layer is less than or equal to the length of the electrolyte layer.

[0073] The catalyst layer 4 can be prepared by processes such as dipping, screen printing, and spraying, and can have a thickness of 15-30 μm. The combined length of the catalyst layer 4 and the fuel electrode layer 3 should be less than or equal to the length of the electrolyte layer 2. The bottom of the electrolyte layer 2 can be exposed downward from the fuel electrode layer 3 and catalyst layer 4. As an example, the catalyst layer is prepared by evenly coating the outer surface of the electrolyte layer with a catalyst layer slurry, drying it, and sintering it at 1000-1300°C for 2-5 hours.

[0074] [Hydrogen permeable membrane]

[0075] A hydrogen permeable membrane parallel to the cell tube axis is added between the fuel electrode layer and the catalyst layer and sealed and fixed to the outer surface of the electrolyte layer. A sealing material is used to encapsulate and isolate the different atmospheres inside and outside the hydrogenation electrochemical reactor and connect the wires and gas path. The hydrogen permeable membrane is composed of Pd, BaCe 0.68 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.02 O 3-δ (BCZYYC), BaCe 0.8- x Zr x Y 0.2 O 3-δ (BCZY, 0.1≤x≤0.8), BaCe 0.8-x Zr x Y 0.1 Yb 0.1 O 3-δ (BCZYYb, 0.1≤x≤0.8) or BaZr 1- x Y x O 3-δ At least one of (BZY, 0.1≤x≤0.5).

[0076] In the present invention, the fuel electrode layer and the catalyst layer are located at different positions in the reactor. During operation, the fuel electrode is located in the higher temperature zone of the furnace and the catalyst layer is located in the lower temperature zone. The ratio of CO2 to H2, the reaction activity and the reaction temperature are regulated according to factors such as the composition, position layout and area size of the fuel electrode layer and the catalyst layer, thereby achieving the regulation of CO2 hydrogenation efficiency, conversion rate and product selectivity. Figure 1 As shown, the electrochemical synthesizer of the present invention forms a tubular structure with an outer fuel electrode layer 3 and a catalyst layer 4, an intermediate electrolyte layer 2, and an innermost air electrode tube 1 serving as a support tube. Before operation, the opening of the air electrode tube 1 is sealed with a sealing material (e.g., ceramic glue or glass ceramic), leaving a gas transmission channel and leading out the wires connected to the air electrode. Wires are also led out from the outer surface of the fuel electrode, connecting the air electrode and fuel electrode wires to the positive and negative poles of an external power supply, respectively. Humidified air is introduced into the air electrode, while an inert purge gas (e.g., nitrogen, argon) and a small amount of H₂ (to maintain a reducing atmosphere) are introduced into the fuel electrode. Dry CO₂ gas is introduced near the catalyst layer 4. When water vapor-containing air is introduced into the electrochemical synthesizer, electrical energy is used to electrolyze water to generate protons, which then migrate through the electrolyte to the fuel electrode 3 to produce hydrogen. The CO₂ introduced from the outside reacts with the purged hydrogen to generate products such as CO and CH₄ in situ. In the present invention, hydrogen generation occurs in the high-temperature section, and CO2 as a reactant can be introduced from the catalyst layer 4 in the low-temperature section to react with the purged H2 to achieve dual efficient conversion of hydrogen production and CO2 hydrogenation reaction.

[0077] Based on the above-mentioned CO2 in-situ hydrogenation electrochemical reactor, the present invention also provides a method for preparing the above-mentioned electrochemical reactor. An air electrode tube 1 serving as a support tube is formed and prepared using a proton conductor material. An electrolyte layer 2 is prepared as an intermediate layer by impregnation and sintering. A fuel electrode layer 3 and a catalyst layer 4 are then prepared by screen printing. This forms a proton conductor-type temperature gradient CO2 in-situ hydrogenation electrochemical reactor. Specifically, the method for preparing the CO2 in-situ hydrogenation electrochemical reactor includes the following steps.

[0078] Prepare the air electrode tube 1. Specifically, the support tube blank can be formed by isostatic pressing or casting, and the support tube blank is calcined at 900-1000°C for 1-4 hours to obtain the support tube.

[0079] The electrolyte layer 2 is prepared on the outer surface of the support tube by slurry impregnation or deposition. Specifically, a slurry of a proton conductor material is evenly coated on the outer surface of the air electrode tube 1 and dried, and then sintered at 600-1300°C for 2-5 hours to obtain the electrolyte layer 2.

[0080] The fuel electrode layer 3 and catalyst layer 4 are screen-printed on the outer surface of the electrolyte layer 2. Specifically, a proton conductor material is mixed with an electron conductor and a binder to prepare a fuel electrode slurry, and a catalyst and a binder are mixed to prepare a catalyst layer slurry. The fuel electrode layer 3 and catalyst layer 4 are then screen-printed onto different areas of the electrolyte layer 2 and sintered at 900-1400°C for 1-4 hours. The fuel electrode layer 3 is located in the high-temperature section of the cell, while the catalyst layer 4 is located in the low-temperature section. The combined length of the fuel electrode layer 3 is equal to or less than that of the electrolyte layer 2.

[0081] A donut-shaped hydrogen permeable membrane 9 is prepared and sealed to the outer surface of the electrolyte layer 2 between the fuel electrode layer 3 and the catalyst layer 4 using a sealing material such as glass or mica. Specifically, the proton conductor material is formed into a donut-shaped green billet using a process such as isostatic pressing or casting. The donut-shaped green billet is then calcined at 1000-1500°C for 2-5 hours to form the donut-shaped hydrogen permeable membrane 9 supporting the donut-shaped tube. The inner diameter of the donut is slightly larger than the outer diameter of the cell tube by 0.2-1.5 mm. A sealing material such as glass or mica is then extruded into the gap to seal it.

[0082] Assemble the electrochemical synthesizer, including connecting wires, sealing, and installing current collecting materials. Then operate the electrochemical synthesizer to perform in-situ CO2 hydrogenation. Specifically, the operating conditions of the electrochemical synthesizer are as follows: (1) Use sealing materials to seal the inner side of the electrochemical synthesizer, leaving only the gas transmission path connected to the outside; (2) After heating the electrochemical synthesizer to the operating temperature (600-750°C) and keeping it warm, introduce air containing water vapor into the inner side of the electrochemical synthesizer, and introduce carrier gas, a small amount of H2, and dry CO2 into the outer side; (3) Connect the inner lead of the electrochemical synthesizer to the positive pole of an external DC power supply, and the outer fuel electrode lead to the negative pole of the external DC power supply. Generally, the electrochemical synthesizer operates in the range of 0.2-1.0V higher than the open circuit voltage to achieve in-situ CO2 hydrogenation.

[0083] Compared with the traditional CO2 hydrogenation process, the advantages of the present invention are mainly reflected in the following aspects:

[0084] (1) In-situ green hydrogenation: Since the H2 produced by water electrolysis reacts directly with CO2, there is no need for hydrogen storage and transportation, which saves costs. The electricity required for water electrolysis can be generated from clean energy, and the entire process does not emit greenhouse gases.

[0085] (2) Flexible temperature control: Utilizing the temperature gradient distribution characteristics of the air electrode support structure and the tubular cell, the fuel electrode is arranged in the high-temperature section outside the tubular cell for hydrogen production, and the CO2 conversion catalyst is arranged in the low-temperature section. The temperature distribution can be controlled in combination with the physical length of the reactor, thereby achieving both high hydrogen yield and high selectivity of CO2 hydrogenation products.

[0086] (3) High energy efficiency: water electrolysis occurs at medium to high temperatures, the energy barrier required for reaction activation is low, and the electrode reaction is rapid;

[0087] (4) Safety: This electrochemical synthesizer is a fully solid-state structure, so there is no danger of leakage, corrosion, or explosion.

[0088] According to the present invention, the electrochemical reactor has a simple structure and only requires a small amount of water during the reaction. H2 is generated in situ to react with CO2. In addition, by utilizing the temperature gradient characteristics of the tubular battery, the catalysts are arranged in different temperature sections, which is conducive to the efficient conversion of CO2. It has the advantages of being clean and environmentally friendly, having a high conversion rate and high selectivity.

[0089] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values ​​exemplified below.

[0090] Example 1

[0091] The structure prepared by the isostatic pressing-high-temperature sintering-impregnation-sintering process is a tubular structure of LSN-BCZY (air support tube 1)-BCZYYC (electrolyte layer 2), and the Ni-BCZY fuel electrode layer 3 and Cu-BZY catalyst layer 4 are coated and sintered in different areas on the surface of the electrolyte 2. The hydrogen generated by high-temperature electrolysis of water reacts with CO2 in situ to generate CO and methane.

[0092] Specifically, the air electrode support tube 1 is prepared by isostatic pressing. The material of the air electrode support tube 1 is (La, Sr)NiO4-BaCe 0.7 Zr 0.1 Y 0.2 After the support tube blank was prepared, the support tube blank was sintered at 1050℃ for 3 hours to obtain a support tube with a length of 20cm, a diameter of about 12mm and a thickness of about 1mm. BaCe was then prepared on the outer surface of the support tube by slurry impregnation. 0.69 Zr 0.1 Y 0.1 Yb 0.1 Cu 0.01 O 3-δ Electrolyte layer 2 (sintered at 1250℃ for 3 hours), and finally Ni-BaCe was prepared on the electrolyte surface by slurry impregnation. 0.7 Zr 0.1 Y0.2 O3 hydrogen electrode layer 3 and Cu-BaZr 0.8 Y 0.2 The catalyst layer 4 of O3 (sintered at 1150°C for 3 hours) has a hydrogen electrode with a length of 8 cm and a thickness of about 25 μm; the catalyst layer has a length of 4 cm and a thickness of about 25 μm. Figure 2 This is the actual object of the temperature gradient CO2 in-situ hydrogenation electrochemical reactor of Example 1.

[0093] Figure 2 The gas chromatography analysis results of the tail gas of the electrochemical synthesizer of Example 1 when it is operated in the temperature range of 750-300°C are shown. Figure 2 As shown, in addition to the CO2 introduced and the H2 generated by the electrolysis reaction, characteristic peaks of CO and methane appeared in the exhaust gas after passing through the catalyst layer.

[0094] The above specific embodiments further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not limited to the scope of protection of the present invention. Without departing from the purpose of the basic characteristics of the present invention, the present invention can be embodied in various forms. Therefore, the embodiments of the present invention are used for illustration rather than limitation. Since the scope of the present invention is defined by the claims rather than the specification, and all changes that fall within the scope defined by the claims or the equivalent range of the scope defined by the claims should be understood to be included in the claims. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer, characterized in that: include: An air electrode support tube having a hollow structure with one end open and the other end closed; the material of the air electrode support tube includes a proton conductor material and an active material; Wet air is introduced into the air electrode side; An electrolyte layer is provided on the outer surface of the air electrode support tube; the electrolyte layer completely covers the outer surface of the air electrode support tube; the electrolyte layer is a proton conductor material; A fuel electrode layer is provided on the outside of the electrolyte layer near the closed end region; the length of the fuel electrode layer is shorter than the length of the electrolyte layer; the material of the fuel electrode layer contains a proton conductor material; A catalyst layer is provided on the outer side of the electrolyte layer near one end of the opening; the length of the catalyst layer is shorter than the length of the electrolyte layer; A hydrogen permeable membrane disposed on the electrolyte layer and used to isolate the fuel electrode layer and the catalyst layer; wherein the hydrogen permeable membrane is disposed between the fuel electrode layer and the catalyst layer; the hydrogen permeable membrane is parallel to the axial direction of the cell tube and is sealed and fixed to the outer surface of the electrolyte layer; The electrochemical synthesizer for in-situ hydrogenation conversion of CO2 also includes a first heating device for placing the fuel electrode layer in a high-temperature heating zone of 750 to 600°C and a second heating device for placing the catalyst layer in a medium-temperature heating zone of 500 to 300°C, wherein the second heating device is provided with a CO2 inlet pipe.

2. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 1, characterized in that The thickness of the air electrode support tube is 0.5 to 1.5 mm; The proton conductor material of the air electrode support tube is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.2, M is at least one of Cu, Y, In, Yb, Sc; the active material of the air electrode support tube is selected from La 1-a Sr a Co 1-b Fe b O3, La 1-c Sr c MnO3、LaNi 1-d Fe d O3, La 2-e Sr e At least one of NiO4, wherein 0≤a≤1, 0≤b≤1, 0≤c≤0.5, 0≤d≤1, and 0≤e≤1.

3. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 2, characterized in that: The mass ratio of the proton conductor material to the active material is 7 / 3 to 3 / 7.

4. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 1, characterized in that The proton conductor material of the electrolyte layer is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.2, and M is at least one of Cu, Y, In, Yb, and Sc; and the thickness of the electrolyte layer is 5 to 50 μm.

5. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 1, characterized in that The materials of the catalyst layer include Ru, Pd, In2O3, Ir, CeO2, ZnO-ZrO2, FeO z , NiO, CuO, CeO2, La2NiO4, M / NO and at least one of the proton conductor materials; wherein FeO z represents one or more oxides of Fe; M in M / NO is at least one of Fe, Co, Ni, Cu, Mo, Rh, Ir, Pd, Pt, Ag, Au, Na, K, and Cs; NO in M / NO is at least one of Al2O3, SiO2, CeO2, TiO2, ZrO2, ZnO, and MgO; the proton conductor material is selected from BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.2, and M is at least one of Cu, Y, In, Yb, and Sc; the content of the proton conductor material in the catalyst layer is 10 to 60 wt%; and the thickness of the catalyst layer is 5 to 50 μm.

6. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 1, characterized in that: The fuel electrode layer is a hydrogen electrode layer; the material of the fuel electrode layer is NiO and a proton conductor material; the mass fraction of NiO in the fuel electrode layer is between 30% and 70%; and the thickness of the fuel electrode layer is 5 to 50 μm.

7. The proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to claim 1, characterized in that The hydrogen permeable membrane is annular; the composition of the hydrogen permeable membrane is selected from Pd, BaCe 1-x-y Zr x M y O3、Ca 0.9 In 0.1 At least one of ZrO3 and LaNbO3, wherein 0 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.2, and M is at least one of Cu, Y, In, Yb, and Sc; the hydrogen permeable membrane has a width of 0.5 to 2.0 cm in the radial direction of the synthesizer and a thickness of 0.2 to 1.5 mm in the axial direction of the synthesizer.

8. A method for preparing CO, methane or methanol by electrochemical reaction, characterized in that: A proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to any one of claims 1 to 7 is used. When the electrochemical synthesizer is in operation, the fuel electrode layer is controlled to be in a high-temperature heating zone of 750 to 600°C, and the catalyst layer is controlled to be in a medium-temperature heating zone of 500 to 300°C. Electric energy is used to electrolyze water vapor to produce hydrogen, and the hydrogen is reacted with CO2 in situ to produce CO, methane or methanol.

9. A method for preparing a proton conductor type CO2 in-situ hydrogenation electrochemical synthesizer according to any one of claims 1 to 7, characterized in that: include: (1) preparing an air electrode layer as a support tube blank, and then calcining it to obtain an air electrode support tube; (2) preparing an electrolyte layer on the outer surface of the air electrode support tube, and then sintering it to obtain a half-cell; (3) preparing a fuel electrode layer and a catalyst layer on the surface of the obtained half-cell, respectively, and then calcining them twice; (4) Prepare a donut-shaped hydrogen permeable membrane ceramic sheet and seal it onto the electrolyte surface between the hydrogen electrode layer and the catalyst layer; (5) Connecting wires and assembling to obtain the electrochemical synthesizer for in-situ hydrogenation conversion of CO2.

10. The preparation method according to claim 9, characterized in that In step (1), the proton conductor material powder and the active material powder are mixed and then subjected to isostatic pressing or casting to prepare a support tube blank; The calcination temperature is 600-1300° C., and the calcination time is 1-4 hours.

11. The preparation method according to claim 9, characterized in that In step (2), after the proton conductor material powder is prepared into an electrolyte layer slurry, the slurry is evenly coated on the outer surface of the air electrode support tube by dipping, screen printing or spraying and dried; the sintering temperature is 900 to 1400°C and the time is 2 to 5 hours.

12. The preparation method according to claim 9, wherein In step (3), Ru, Pd, In2O3, Ir, CeO2, ZnO-ZrO2, FeO z At least one of NiO, CuO, CeO2, La2NiO4, M / NO and proton conductor material powder are prepared into a catalytic layer slurry; wherein FeO z Represents one or more oxides of Fe; M in M / NO is at least one of Fe, Co, Ni, Cu, Mo, Rh, Ir, Pd, Pt, Ag, Au, Na, K, and Cs, and NO in M / NO is at least one of Al2O3, SiO2, CeO2, TiO2, ZrO2, ZnO, and MgO; after preparing NiO powder and proton conductor material powder into fuel electrode layer slurry, the fuel electrode layer slurry and catalyst layer slurry are respectively and evenly coated on the outer surface of the electrolyte layer by impregnation, screen printing or spraying and dried; the temperature of the secondary calcination is 900-1400°C, and the time is 1-4 hours.

13. The preparation method according to claim 9, wherein In step (4), Pd powder, BaCe 1-x-y Zr x M y O3 powder, Ca 0.9 In 0.1 At least one of ZrO3 powder and LaNbO3 powder is mixed, and a circular ceramic sheet blank is prepared by isostatic pressing or casting, and then sintered at 900-1500°C for 2-5 hours to obtain the hydrogen permeable membrane; wherein 0 ≤x≤0.8, 0≤y≤0.2.

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