Pyrolytic decoupling of series microreactor devices and their preparation and use

Abstract

The present application relates to a pyrolysis decoupling series micro-reactor device and its preparation and application, comprising: a multi-channel pipe fuel electrode matrix is prepared by using phase inversion assisted extrusion method; SOEC is formed on the first shaft section of the fuel electrode matrix to obtain a ceramic pipe; Ru-doped CeO2 methane catalyst is loaded on the entire inner surface of the ceramic pipe to obtain a reactor monomer; the reactor monomer is placed in a heating furnace, the heating furnace comprises a first heating chamber, an insulation chamber and a second heating chamber arranged in sequence, and the temperature control of the two heating chambers is independent; the first heating chamber is used for accommodating and heating the first shaft section to form a CO2 high-temperature electrolysis zone; the second heating chamber is used for accommodating and heating the second shaft section loaded with only the methane catalyst to form a low-temperature methanation reaction; the insulation chamber insulates the axial heat flow of the two reaction zones. The present application solves the thermodynamic conflict between high-temperature activation and low-temperature methanation in the carbon dioxide methanation process in the prior art, and realizes efficient and stable carbon dioxide hydrogenation to produce methane.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide conversion and renewable energy storage technology, specifically to a thermally decoupled series microreactor device and its preparation and application. Background Technology

[0002] Among the many power-to-X (Power-to-X) technologies, the conversion of CO2 to methane via hydrogenation (Sabatier process) has extremely high industrial value. Methane is not only a universal energy carrier but can also be directly connected to existing natural gas infrastructure, enabling long-distance transmission and long-term storage of renewable energy. However, in actual conversion processes, CO2 methanation faces a severe challenge of thermodynamic-kinetic mismatch. From a kinetic perspective, the chemical properties of CO2 molecules are extremely stable, and the activation of its C=O bonds often requires high reaction temperatures (typically >600°C) to overcome the activation energy barrier. However, from a thermodynamic perspective, the methanation reaction (CO2 + 4H2 ⇌ CH4 + 2H2O) is a strongly exothermic process. According to Le Chatelier's principle, high temperatures significantly inhibit the shift of chemical equilibrium towards the product side, leading to a decrease in methane selectivity and inducing side reactions (such as the reverse water-gas shift reaction). Traditional single-stage reactors attempt to achieve both high-temperature activation and low-temperature conversion within the same space, which inevitably leads to a trade-off between activity and selectivity, severely limiting the overall space-time yield (STY) of the system.

[0003] In the prior art, see CN202510301577.4, which proposes a micro-cellular tubular series reactor, attempting to achieve a series reaction by arranging electrolysis units and catalytic units on the same microtube. Although this scheme initially achieves spatial functional partitioning, it still has the following significant drawbacks in practical applications: First, the precision of thermal management and decoupling is insufficient. Existing technologies use microtube structures, and the temperature gradient between the high-temperature and low-temperature regions is difficult to maintain precisely, resulting in severe "thermal interference" and making it impossible for both reactions to be within their respective optimal thermodynamic windows.

[0004] Secondly, the long-term stability of the catalytic interface is poor. Existing technologies typically employ traditional impregnation methods to support catalysts (such as the Ni-Cu-Ce system), where metal particles are simply "accumulated" on the support surface, representing physical adsorption. The interaction between the metal active sites and the support is weak. Under long-term high-temperature electrochemical and intensely exothermic environments, the active sites are highly susceptible to migration and loss.

[0005] Therefore, in microscale reaction systems, how to construct a reaction environment with multi-scale constraint effects—that is, to enhance heat transfer at the mesoscale through special channel structures to eliminate hot spots, and to improve site stability at the nanoscale through strong metal-support interaction (SMSI)—is a core technical challenge that urgently needs to be solved in the field of electrocatalytic carbon dioxide conversion. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a thermally decoupled series microreactor device and its preparation and application, which solves the thermodynamic conflict between high-temperature activation and low-temperature methanation in the carbon dioxide methanation process, as well as the catalyst deactivation problem caused by strong exothermic reaction, thereby achieving efficient and stable carbon dioxide hydrogenation to methane production.

[0007] The technical solution adopted in this invention is as follows: This invention provides a method for preparing a thermally decoupled series microreactor device, comprising: Multichannel tubular fuel electrode substrate was prepared by phase inversion-assisted extrusion. An electrolyte layer is disposed on the first axial section of the fuel electrode substrate, and an air electrode is disposed on the electrolyte layer to obtain a ceramic tube; A methane catalyst is loaded onto the entire inner surface of the ceramic tube using an impregnation method to obtain a reactor monomer, on which only the methane catalyst is loaded, and the region separated from the first shaft segment is the second shaft segment; the methane catalyst is a Ru-doped CeO2 catalyst; The reactor unit is placed in a heating furnace, which includes a first heating chamber, an insulation chamber, and a second heating chamber arranged in sequence, with independent temperature control for the two heating chambers; The first heating chamber is used to contain and heat the first shaft segment to form a first reaction zone for high-temperature CO2 electrolysis. The second heating chamber is used to contain and heat the second shaft segment to form a second reaction zone for carrying out a low-temperature methanation reaction in series with the high-temperature CO2 electrolysis. The insulation chamber is used to isolate the axial heat flow between the two shaft segments, so that the two reaction zones are in their respective thermodynamically optimal windows.

[0008] The preferred technical solution is: The loading of the methane catalyst includes: Ru-doped CeO2 catalyst was prepared by in-situ exsolution process: cerium nitrate and ruthenium nitrite nitrite were dissolved in deionized water according to stoichiometric ratio, citric acid was added as a complexing agent, and the mixture was stirred evenly to form a catalyst solution; The catalyst solution is loaded onto the entire inner surface of the ceramic tube by impregnation. After each impregnation, the tube is dried. This process is repeated multiple times until the catalyst loading reaches the set value. Then, calcination is performed to allow the Ru nanoparticles to exsolve in situ and anchor onto the surface of the CeO2 support.

[0009] The molar ratio of metal ions to citric acid in the catalyst solution is 1:1.5; the catalyst loading is set at 4.6 wt%.

[0010] The calcination temperature is 900°C.

[0011] The heat insulation chamber is made of quartz wool, which separates the first and second heating chambers along the axial direction and wraps the gap area between the first and second shaft segments.

[0012] The preparation of the multi-channel tubular fuel electrode substrate using phase inversion-assisted extrusion includes: NiO powder, YSZ powder, or a mixture of YSZ powder and polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and a binder are mixed in a certain proportion and then ball-milled to prepare a film liquid; the vacuum-treated film liquid and a coagulant are extruded using a multi-channel spinneret to form a precursor; the precursor is sintered to form the fuel electrode substrate; The mass ratio of NiO powder, YSZ powder, polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and binder is (90~110):(60~70):(0~2.5):(45~55):(10~20).

[0013] An electrolyte layer is disposed on the first axial segment of the fuel electrode substrate, and an air electrode is disposed on the electrolyte layer, including: YSZ, PVB and PEG powders were added to anhydrous ethanol and ball-milled to obtain YSZ electrolyte slurry; GDC, PVB and PEG powders were added to anhydrous ethanol and ball-milled to obtain GDC barrier layer slurry; GDC, LSCF and ethylene glycol were ball-milled and mixed to obtain an air electrode slurry; The YSZ electrolyte is coated onto the first axial section of the fuel electrode substrate by impregnation. After thorough drying, the GDC barrier layer slurry is coated onto the substrate. After drying again, the substrate is sintered to form an electrolyte film. Then, the air electrode slurry is brushed onto the electrolyte film and sintered again to obtain the ceramic tube.

[0014] The present invention also provides a thermally decoupled tandem microreactor device prepared according to the preparation method described above.

[0015] The present invention also provides a method for applying the aforementioned thermally decoupled series microreactor device, comprising: The gas to be treated is introduced into the reactor unit from one end, and CO2 is electrolyzed at high temperature in the first reaction zone at 650-750°C. The intermediate product generated by the high temperature electrolysis enters the second reaction zone along the axial direction of the reactor unit, and is converted into methane at 200-300°C using a Ru-doped CeO2 catalyst.

[0016] The CO2 gas to be processed includes a mixture of CO2 and H2.

[0017] The technical solution of the present invention can achieve at least some of the following beneficial effects: This invention utilizes physical barriers to achieve spatial-thermal decoupling, combines this with a multi-channel structure in the fuel electrode substrate to enhance radial heat dissipation, and employs an in-situ exsolution strategy to anchor catalytic active sites, thus constructing a full-scale confinement environment from the mesoscopic to the nanoscale. This series of techniques are coupled together to synergistically solve the shortcomings of existing technologies in thermal management runaway and interfacial instability, achieving a significant leap in carbon dioxide methanation efficiency. Specifically, this is reflected in the following aspects: This invention incorporates a quartz insulation chamber within the heating furnace to isolate axial heat flow. This allows the first reaction zone (electrolysis zone) to maintain high current density for CO2 activation, while the second reaction zone (catalytic zone) maintains low temperature and high selectivity. This achieves precise axial spatial-thermal decoupling, overcoming thermodynamic equilibrium limitations. It completely resolves the contradiction between the CO2 activation energy barrier and the "thermodynamic limitation" of the exothermic methanation reaction within a single temperature range, resulting in a nearly 40% improvement in methane selectivity compared to existing technologies. It effectively avoids the adverse water-gas shift side reactions caused by the limitations of temperature zone control in existing technologies, which result in severe axial thermal interference and the inability to maintain a temperature difference of several hundred degrees within a very short distance.

[0018] This invention abandons the traditional impregnation loading method with weak bonding in existing technologies, and uses an in-situ exsolution process to precipitate Ru nanoparticles from the CeO2 lattice. In-situ exsolution of Ru nanoparticles is achieved by calcining Ru-doped CeO2 (CR5O) at 900°C. This nanoscale in-situ exsolution technology constructs an ultra-stable catalytic interface. During high-temperature reduction, Ru nanoparticles precipitate from the CeO2 lattice and are "semi-embedded" in the lattice grooves, providing ultra-strong metal-support interaction (SMSI). Compared with the surface-stacking loading of existing technologies, the "nano-embedded" anchoring structure of this invention forms a nanoscale confinement effect with SMSI. Experiments show that under this dual constraint, the active sites did not exhibit significant aggregation or migration during high-throughput operation for up to 250 hours. The coupling between the nano-confined sites and the mesoscopic confined heat transfer structure provides mutual support and exhibits strong anti-sintering ability, ensuring long-term stability of methane yield and long-term stability of the system under high stress conditions.

[0019] This invention achieves significant technological advancements through deep coupling of a multi-scale constraint strategy and a space-thermal decoupling design. The multi-scale characteristic coupling results in extremely high spatiotemporal yields and industrialization potential. Due to the synergistic multiplier effect between the high-throughput mass transfer capability of the four-channel structure and the high catalytic activity of the in-situ exsolution sites, this invention achieves a yield as high as 621 mmol·gcat under decoupling conditions of 750 °C / 250 °C. -1 ·h -1 The system boasts high methane space-time yield (STY), high system integration, and low heat loss, providing a highly competitive technical solution for large-scale electrocatalytic conversion of carbon dioxide and energy storage.

[0020] Compared to existing technologies that only load catalysts on a single reaction zone, i.e., only catalyzing the chemical reactions in the fuel synthesis stage, this invention loads Ru-doped CeO2 catalysts throughout the entire reactor, improving electrolysis efficiency while enhancing the fuel synthesis reaction. Furthermore, existing technologies typically employ a Ni-Cu-Ce system with high loading and impregnation concentrations, reaching 25% of the reactor's total mass. This invention uses a Ru@CeO2 system, with the loading controlled at 4.6 wt%.

[0021] Other features and advantages of the invention will be set forth in the following description or may be learned by practicing the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the reactor device in Embodiment 1 of the present invention.

[0023] Figure 2 for Figure 1 Temperature distribution map of the medium-temperature test area.

[0024] Figure 3 This is a structural feature diagram of the reactor unit in Embodiment 1 of the present invention.

[0025] Figure 4 The impedance curves of the reactor monomer in the first reaction zone (OCV) of Embodiment 1 and Comparative Example 1 of the present invention are shown.

[0026] Figure 5 This is a graph showing the change in current density as a function of voltage during CO2 electrolysis at a voltage of 1.55 V in the first reaction zone of the reactor unit in Example 1 and Comparative Example 1 of the present invention.

[0027] Figure 6 The graph shows the change in current density with voltage during CO2 electrolysis under different gas inlet ratios when applying voltage to the first reaction zone of the reactor unit in Embodiment 1 of the present invention.

[0028] Figure 7The figure shows the results of a continuous 250-hour operation test of the reactor device in Embodiment 1 of the present invention.

[0029] Explanation of reference numerals in the attached drawings: 1. Fuel electrode substrate; 2. Electrolyte layer; 3. Air electrode; 4. First heating chamber; 5. Insulation chamber; 6. Second heating chamber; 7. First reaction zone; 8. Second reaction zone; 9. Thermal insulation layer; 10. Silver wire. Detailed Implementation

[0030] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0031] Example 1 This embodiment provides a method for preparing a thermally decoupled series microreactor device, including: S1. A multi-channel tubular fuel electrode substrate is prepared using a phase inversion-assisted extrusion method. A preferred method includes the following steps: S11. Mix NiO powder, YSZ powder, N-methylpyrrolidone, and binder in a certain proportion and then ball mill, or mix NiO powder, YSZ powder, a mixture of polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and binder in a certain proportion and then ball mill to prepare a film liquid; The membrane solution obtained after ball milling was subjected to vacuum degassing treatment for 2 hours; S12. The vacuum-treated film liquid and coagulant are extruded using a four-channel spinneret to form a precursor.

[0032] Specifically, the membrane solution and coagulant are simultaneously extruded from the interlayer gap of the spinning head and the inner tube, respectively. The distance between the spinning head and the surface of the deionized water is 1 cm. The precursor formed has a minimum thickness of 70 μm. Preferably, the extrusion rate of the coagulant is 9–30 mL / min, and the extrusion rate of the membrane solution is 9–20 mL / min.

[0033] Specifically, the precursor is soaked in deionized water for 24 hours to ensure the phase transformation process is complete; then the precursor is straightened on a custom acrylic plate and cut to 12.5cm after drying for 24 hours.

[0034] S13. Sintering treatment of the precursor: sintering at 600°C for 2 hours to completely remove the organic binder, followed by sintering at 1200°C for 5 hours to enhance mechanical strength, finally forming the fuel electrode matrix.

[0035] The mass ratio of NiO powder, YSZ powder, polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and binder is (90~110):(60~70):(0~2.5):(45~55):(10~20), with a preferred ratio of 135:90:100:2:30. The adhesive is one or two of polymethyl methacrylate, high-density polyethylene, polypropylene, polyethylene wax, polystyrene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polyvinyl butyral, and polyethyleneimine; in this embodiment, polyvinyl butyral is preferred.

[0036] The coagulant is an aqueous solution of polyvinyl alcohol, and the mass ratio of polyvinyl alcohol to water is (1~3):14.

[0037] The precursor features a unique four-channel structure, with channels typically having elliptical cross-sections. Radially arranged finger-like micropores are distributed within the tube wall, forming a mesoscale confinement zone designed to enhance radial heat transfer during the reaction process, rapidly remove heat generated by the methanation reaction, and prevent localized hot spots.

[0038] The final fuel electrode substrate is a multi-channel microtubular ceramic hollow fiber membrane, which has dense finger-like pores on its cross-section and dense sponge-like pores on the inner wall of the elliptical channel.

[0039] S2. An electrolyte layer is formed in the first axial segment of the fuel electrode substrate, and an air electrode is formed on the electrolyte layer to obtain a ceramic tube, thereby obtaining a solid oxide electrolyzer (SOEC) structure in the first axial segment of the ceramic tube. As a preferred embodiment, this includes: S21. Add 20g YSZ, 2g PVB and 1g PEG powder to 100g anhydrous ethanol, and ball mill for 24 hours to obtain YSZ electrolyte slurry; 20g GDC, 2g PVB and 1g PEG powder were added to 100g anhydrous ethanol and ball-milled for 24 hours to obtain GDC barrier layer slurry. GDC, LSCF and ethylene glycol were ball-milled at a mass ratio of 5:5:6 for 24 hours to obtain an air electrode slurry. S22. The YSZ electrolyte is coated onto the first axial section of the fuel electrode substrate by impregnation. After thorough drying, the GDC barrier layer slurry is coated on. After drying again, the sintering is carried out at 1450°C or 1500°C for 5 hours to form a dense electrolyte film. Then, the air electrode slurry is brushed onto the electrolyte film and sintered at 1000°C for 2 hours.

[0040] S3. A methane catalyst is loaded onto the entire inner surface of the ceramic tube using an impregnation method to obtain a reactor monomer, on which only the methane catalyst is loaded, and the region separated from the first shaft segment is the second shaft segment; the methane catalyst is a Ru-doped CeO2 catalyst, which can be denoted as Ru@CeO2 catalyst. As a preferred embodiment, it includes: S31. Preparation of Ru-doped CeO2 catalyst by in-situ exsolution process: Cerium nitrate Ce(NO3)3·6H2O and nitrosylruthenium nitrate Ru(NO)(NO3) are mixed in stoichiometric ratio. x (OH) y Dissolve in deionized water, add citric acid as a complexing agent, and stir for 24 hours to form a catalyst solution.

[0041] The catalyst solution is specifically 1 mol·L⁻¹ -1 Ce 0.95 Ru 0.05 The solution is an O2 (CR5O) solution, wherein the molar ratio of metal ions to citric acid is 1:1.5.

[0042] S32. The catalyst solution is loaded onto the entire inner surface of the ceramic tube by impregnation. After each impregnation, the tube is dried at 80°C for 12 hours. This process is repeated multiple times until the catalyst loading reaches 4.6 wt%.

[0043] S33. Finally, calcination at 900°C for 4 hours allows Ru nanoparticles to exsolve in situ and anchor on the CeO2 support surface.

[0044] Step S3 involves calcining a cerium source and a ruthenium source in a specific ratio at 900°C, causing Ru nanoparticles to desolvate from the CeO2 lattice and anchor in the lattice "grooves". This structure effectively prevents the aggregation of metal particles during long-term operation through physical anchoring and strong metal-support interaction (SMSI).

[0045] S4. The reactor unit is placed in a heating furnace, which includes a first heating chamber, an insulation chamber, and a second heating chamber arranged in sequence, with independent temperature control for the two heating chambers; The first heating chamber is used to contain and heat the first shaft segment to form a first reaction zone for high-temperature CO2 electrolysis. The second heating chamber is used to contain and heat the second shaft segment to form a second reaction zone for carrying out a low-temperature methanation reaction in series with the high-temperature CO2 electrolysis. The insulation chamber is used to isolate the axial heat flow between the two shaft segments, so that the two reaction zones are in their respective thermodynamically optimal windows.

[0046] Preferably, the heat insulation chamber is made of quartz wool, which separates the first and second heating chambers along the axial direction and wraps the gap area between the first shaft segment and the second shaft segment.

[0047] The reaction apparatus in this embodiment is as follows: Figure 1As shown. In specific implementation, insulation layers 9 are respectively installed at both ends of the heating furnace. The heating furnace is arranged axially with a first heating chamber 4, an insulation chamber 5, and a second heating chamber 6. The first axial section of the reactor unit is located in the first heating chamber 4, forming a first reaction zone 7, and the second axial section of the reactor unit is located in the second heating chamber 6, forming a second reaction zone 8. The two reaction zones are isolated from each other by an isolation chamber 5. In specific application, the fuel electrode and the air electrode are connected to the power supply through a silver wire 10. The gas to be treated is input from one end of the reactor unit, and the treated gas is discharged from the other end.

[0048] To verify the effectiveness of the segmented temperature control in the reactor, six temperature testing points, T1 to T6, were set along the axial direction. The actual temperature measurements at each testing point at the set temperature are shown in [reference needed]. Figure 2 .Depend on Figure 2 It can be seen that the reactor device in this embodiment has excellent space-thermal decoupling temperature control capability, ensuring that the endothermic electrolysis process and the exothermic methanation process can operate efficiently within their respective independent optimal thermodynamic windows without interfering with each other, thereby achieving a leapfrog improvement in the overall space-time yield of the system.

[0049] Figure 3 This reflects the scale-confined structural characteristics of the reactor unit in this embodiment. Figure 3 The upper middle section shows the structural diagram of the reactor unit, in which an electrolyte layer 2 and an air electrode 3 are sequentially arranged on the fuel electrode substrate 1. The methane catalyst is located on the inner wall of the tube and is therefore not shown. The preferred dimensions of the reactor unit obtained in this embodiment are: an outer diameter of approximately 2 mm; a total length of 11.5 cm, wherein the electrolysis unit ( Figure 1 The length of the dotted line on the left side is 6cm, the electrolyte length is 5cm, and the air electrode length is 2cm.

[0050] Figure 3 The middle section shows a SEM image of the four-channel symmetrical structure and radially arranged finger-like micropores (mesoscopic confinement) formed by the phase transformation method. Figure 3 The image on the right shows the morphology (nanoconfined) of Ru nanoparticles after calcination at 900°C, where they exsolve in situ and are semi-embedded and anchored in the "grooves" of the CeO2 lattice. Ultimately, the methane catalyst is supported in the porous structure of the NiO-YSZ fuel electrode.

[0051] Comparative Example 1 This comparative example provides a method for preparing a thermally decoupled tandem microreactor device. While other process steps and parameters are the same as in Example 1, the difference lies in: In Example 1, methane catalyst was loaded only in the second reaction zone, whereas in Example 1, methane catalyst was loaded on the entire inner surface of the ceramic tube.

[0052] CO2 electrolysis experiments were conducted using the reactor devices prepared in Example 1 and Comparative Example 1 to verify the superiority of the reactor unit in Example 1. Specifically, the experiments included: (1) CO2 electrolysis was performed using the reactor monomers prepared in Example 1 and Comparative Example 1 under specific inlet gas components, including: After assembling the reactor unit, it is placed in the heating furnace, with the first shaft section located in the first heating chamber; According to 5℃·min -1 The first heating chamber is heated to 650°C at a rate of [missing information], during which 50 ml / min is introduced. -1 N2; When the furnace temperature reaches 650℃, the gas is switched to H2 at a flow rate of 50 ml / min. -1 It is used to reduce NiO in the fuel electrode matrix to Ni. After 3 hours of reduction, the first heating chamber is heated at 5℃·min. -1 The temperature is increased to 750°C; silver wires drawn from the fuel electrode and air electrode are connected to the electrochemical workstation for battery mode operation.

[0053] The current-voltage characteristic curves were obtained using the linear sweep current-voltage method. The test voltage in battery mode ranged from open-circuit voltage (OCV) to 0V, with a scan rate of 0.01V·s. -1 The electrochemical impedance spectroscopy test frequency was 10. 5 Up to 10 -1 Hz.

[0054] Maintain an intake of 50 ml / min during battery mode performance. -1 H2, start electrolysis mode test, switch the inlet gas to a mixture of CO2 and H2 (50ml·min) -1 (60% CO2 - 40% H2).

[0055] The test voltage range for electrolysis mode is from OCV to 1.55V, and the scan rate is consistent with that for battery mode. Gas chromatography (GC) is used to detect the components of the exhaust gas, and the exhaust gas passes through a drying tube to remove the water vapor it carries before entering the GC.

[0056] Impedance spectra of reactor single cells are as follows Figure 4 As shown in the figure. The curve of current density versus voltage during CO2 electrolysis under SOEC mode with a voltage of 1.55 V is shown in the figure. Figure 5 As shown. Figure 4 and Figure 5 In the figures, REF and Ru@CeO2-REF represent the test results of the single-cell reactors in Comparative Example 1 and Example 1, respectively. (From...) Figure 4 It can be seen that the impedance of the single cell in the reactor of Example 1 is significantly lower than that of Comparative Example 1. (From...) Figure 5It can be seen that the electrolysis current of the single cell in the reactor of Example 1 is significantly higher than that of Comparative Example 1. This indicates that the Ru@CeO2 catalyst has a significant enhancing effect on the electrochemical performance of the fuel electrode at high temperatures, effectively improving the CO2 processing throughput of the electrolysis section.

[0057] (2) CO2 electrolysis was carried out using the reactor unit prepared in Example 1 under different inlet gas components. Following the method in step (1), the inlet gas was switched to 50 ml·min in the electrolysis mode. -1 Multiple tests were conducted on mixtures of H2 and CO2 with different components. The ratios of H2 to CO2 in the mixtures were 8:2, 7:3, 6:4, and 4:6 in the different tests.

[0058] The curves showing the current density versus voltage during the electrolysis of CO2 with a SOEC voltage of 1.55 V under test conditions of mixed H2 and CO2 with different components are as follows: Figure 6 As shown. By Figure 6 The effect of different inlet gas molar ratios on current density is evident. Results show that as the H2 ratio increases, the open-circuit voltage (OCV) decreases, and the auxiliary reduction effect is enhanced. At 1.55V, the reducing inlet gas ensures the chemical stability of the Ni electrode under high current density operation, avoiding the increased polarization caused by water vapor in existing technologies.

[0059] Example 2 This embodiment provides an application of the thermally decoupled series microreactor device of Example 1 for CO2 methanation, comprising: placing a reactor unit in a heating furnace, introducing the gas to be treated into the reactor unit from one end, and causing CO2 to undergo high-temperature electrolysis at 650-750°C in the first reaction zone; the intermediate product generated by the high-temperature electrolysis enters the second reaction zone along the axial direction of the reactor unit, and is converted into methane at 200-300°C using a Ru-doped CeO2 catalyst. As a preferred embodiment, the following steps are included: According to 5℃·min -1 The first and second reaction zones were heated to 650 °C at a rate of [missing information], with 50 ml / min being introduced during the heating process. -1 When the furnace temperature reaches 650℃, the gas is switched to H2 at a flow rate of 50 ml / min. -1 It is used to reduce NiO in the fuel electrode to Ni, and at the same time reduce the catalyst CR5O to CR5O, which dissolves Ru nanoparticles in situ. 5-x O(Ru@CR) 5-x O); After reduction for 3 hours, the furnace temperature of the first reaction zone is adjusted according to 5 °C·min. -1 The temperature was increased to 750 °C at a heating rate of 5 °C / min. The furnace temperature in the second reaction zone was maintained at 5 °C / min. -1 Heating to 250 ℃ at a cooling rate; Silver wires leading from the fuel and air electrodes were connected to the electrochemical workstation. The voltammetric characteristic curves were obtained using a linear sweep voltammetry method, with the test voltage in battery mode ranging from open-circuit voltage (OCV) to 0V, and a scan rate of 0.01 V·s. -1 The electrochemical impedance spectroscopy test frequency was 10. 5 Up to 10 -1 Hz.

[0060] Maintain an intake of 50 ml / min during battery mode performance. -1 For electrolysis mode testing, the inlet gas was switched to 50 ml / min. -1 Mixtures of H2 and CO2 with different components (H2 to CO2 ratios of 8:2, 7:3, 6:4, and 4:6, respectively).

[0061] The test voltage range for electrolysis mode is OCV to 1.55V, and the scan rate is consistent with that of battery mode. Gas chromatography (GC) was used to analyze the exhaust gas composition; the exhaust gas passed through a drying tube before entering the GC to remove any carried water vapor. Long-term stability testing was conducted in the first reaction zone electrolysis section at 750 °C with an inlet gas composition of 40% CO2 and 60% H2.

[0062] Experimental results show that, under decoupled conditions of 750 °C / 250 °C, the reactor achieved a yield as high as 621 mmol·g. cat -1 ·h -1 The methane space-time yield (STY) was significantly improved. Compared to conventional reactors without spatial decoupling capabilities, the methane selectivity was increased by nearly 40%.

[0063] like Figure 7 As shown, during a continuous 250-hour run test, under decoupled conditions of 750°C in zone 1 and 250°C in zone 2, the methane space-time yield remained stable at approximately 621 mmol g. cat -1 h -1 No significant catalyst deactivation was observed, and the current and product flow rate remained stable. This demonstrates the superiority of the spatial-thermal decoupling design and in-situ exsolution sites in this Example 1 in terms of anti-sintering and overcoming thermodynamic limitations. Transmission electron microscopy (TEM) analysis showed that, due to the anchoring effect of the nanoscale "grooves" formed by in-situ exsolution, the Ru nanoparticles remained highly dispersed after long-term operation, effectively inhibiting the sintering of metal particles.

[0064] In summary, this embodiment fundamentally solves the problems of oxidation deactivation of Ni-based electrodes and competitive adsorption of water vapor on catalytic sites by optimizing the inlet gas composition from the commonly used oxidizing CO2 / H2O to a reducing CO2 / H2. Simultaneously, a highly stable Ru@CeO2 nanostructure was constructed using in-situ exsolution technology, and a full-segment loading strategy was adopted to ensure the catalyst maintains electrocatalytic activity at high temperatures, significantly improving CO2 electrolysis efficiency. This synergistic design of "reducing inlet gas + in-situ nanosites + full-segment catalytic enhancement," combined with a four-channel thin-walled microtube structure, enables the system to achieve improved electrolysis and conversion efficiency at 1.55V, demonstrating excellent engineering application prospects.

[0065] It will be understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a thermally decoupled series microreactor device, characterized in that, include: Multichannel tubular fuel electrode substrate was prepared by phase inversion-assisted extrusion. An electrolyte layer is disposed on the first axial section of the fuel electrode substrate, and an air electrode is disposed on the electrolyte layer to obtain a ceramic tube; A methane catalyst is loaded onto the entire inner surface of the ceramic tube using an impregnation method to obtain a reactor monomer, on which only the methane catalyst is loaded, and the region separated from the first shaft segment is the second shaft segment; the methane catalyst is a Ru-doped CeO2 catalyst; The reactor unit is placed in a heating furnace, which includes a first heating chamber, an insulation chamber, and a second heating chamber arranged in sequence, with independent temperature control for the two heating chambers; The first heating chamber is used to contain and heat the first shaft segment to form a first reaction zone for high-temperature CO2 electrolysis. The second heating chamber is used to contain and heat the second shaft segment to form a second reaction zone for carrying out a low-temperature methanation reaction in series with the high-temperature CO2 electrolysis. The insulation chamber is used to isolate the axial heat flow between the two shaft segments, so that the two reaction zones are in their respective thermodynamically optimal windows.

2. The preparation method according to claim 1, characterized in that, The loading of the methane catalyst includes: Ru-doped CeO2 catalyst was prepared by in-situ exsolution process: cerium nitrate and ruthenium nitrite nitrite were dissolved in deionized water according to stoichiometric ratio, citric acid was added as a complexing agent, and the mixture was stirred evenly to form a catalyst solution; The catalyst solution is loaded onto the entire inner surface of the ceramic tube by impregnation. After each impregnation, the tube is dried. This process is repeated multiple times until the catalyst loading reaches the set value. Then, calcination is performed to allow the Ru nanoparticles to exsolve in situ and anchor onto the surface of the CeO2 support.

3. The preparation method according to claim 2, characterized in that, The molar ratio of metal ions to citric acid in the catalyst solution is 1:1.5; the catalyst loading is set at 4.6 wt%.

4. The preparation method according to claim 2, characterized in that, The calcination temperature is 900°C.

5. The preparation method according to claim 1, characterized in that, The heat insulation chamber is made of quartz wool, which separates the first and second heating chambers along the axial direction and wraps the gap area between the first and second shaft segments.

6. The preparation method according to claim 1, characterized in that, The preparation of the multi-channel tubular fuel electrode substrate using phase inversion-assisted extrusion includes: NiO powder, YSZ powder, or a mixture of YSZ powder and polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and a binder are mixed in a certain proportion and then ball-milled to prepare a film liquid; the vacuum-treated film liquid and a coagulant are extruded using a multi-channel spinneret to form a precursor; the precursor is sintered to form the fuel electrode substrate; The mass ratio of NiO powder, YSZ powder, polyethylene glycol-30-dipolyhydroxystearate, N-methylpyrrolidone, and binder is (90~110):(60~70):(0~2.5):(45~55):(10~20).

7. The preparation method according to claim 1, characterized in that, An electrolyte layer is disposed on the first axial segment of the fuel electrode substrate, and an air electrode is disposed on the electrolyte layer, including: YSZ, PVB and PEG powders were added to anhydrous ethanol and ball-milled to obtain YSZ electrolyte slurry; GDC, PVB and PEG powders were added to anhydrous ethanol and ball-milled to obtain GDC barrier layer slurry; GDC, LSCF and ethylene glycol were ball-milled and mixed to obtain an air electrode slurry; The YSZ electrolyte is coated onto the first axial section of the fuel electrode substrate by impregnation. After thorough drying, the GDC barrier layer slurry is coated onto the substrate. After drying again, the substrate is sintered to form an electrolyte film. Then, the air electrode slurry is brushed onto the electrolyte film and sintered again to obtain the ceramic tube.

8. A thermally decoupled tandem microreactor device prepared by the preparation method according to any one of claims 1-7.

9. A method for applying the thermally decoupled series microreactor device according to claim 8, characterized in that, include: The gas to be treated is introduced into the reactor unit from one end, so that CO2 is electrolyzed at a high temperature of 650-750°C in the first reaction zone. The intermediate product generated by high-temperature electrolysis enters the second reaction zone along the axial direction of the reactor monomer, and is converted into methane at 200-300℃ using a Ru-doped CeO2 catalyst.

10. The application method according to claim 9, characterized in that, The CO2 gas to be processed includes a mixture of CO2 and H2.

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