A synergistic modification method for improving the performance of ceramic membrane reactor for CO2 decomposition

Abstract

This invention discloses a synergistic modification method for improving the CO2 decomposition performance of ceramic membrane reactors. By preparing a dense membrane substrate containing fluorite and B-site-doped perovskite phases, and constructing an A-site-defect perovskite porous coating on the CO2 feed side, the synergistic regulation of substrate stabilization and surface activation is achieved. The B-site-doped membrane substrate provides a stable transmembrane transport channel for oxygen species generated during CO2 decomposition, while the A-site-defect coating enhances the generation process of oxygen species on the CO2 feed side. Together, they reduce the resistance to surface reactions and oxygen migration on the CO2 side, enabling the membrane reactor to maintain long-term stable operation even at high CO2 decomposition rates. This invention provides an effective substrate-coating synergistic modification method for improving the CO2 decomposition rate and long-term operational stability of membrane reactors.

Description

Technical Field

[0001] This invention belongs to the technical fields of CO2 conversion and utilization, mixed ion-electron conductor oxygen-permeable membranes, and high-temperature membrane reactors. Specifically, it relates to a synergistic modification method for improving the CO2 decomposition performance of ceramic membrane reactors, and more particularly to a synergistic modification method for membrane reactors that regulates membrane matrix stability by B-site doping of perovskite phase and improves CO2 adsorption activation and surface exchange reaction rates by using a porous perovskite coating with A-site defects on the CO2 feed side. Background Technology

[0002] With the continuous increase in fossil energy consumption and CO2 emissions, the development of efficient CO2 conversion and utilization technologies is of great significance for alleviating carbon emission pressure and producing high-value-added carbon-based chemicals. Thermochemical decomposition of CO2 can directly convert CO2 into CO, but this reaction is limited by thermodynamic equilibrium, and if the generated oxygen species are not removed in time, they are prone to reverse reaction with CO. Dense oxygen-permeable membrane reactors can utilize the selective oxygen ion transport capability of the membrane material to continuously migrate the oxygen species generated from CO2 decomposition to the permeate side. When CH4 is introduced into the permeate side, the permeated oxygen further participates in the partial oxidation of methane to produce CO and H2, thereby enhancing the oxidation potential gradient across the membrane and achieving synergistic coupling between CO2 decomposition and syngas production.

[0003] Fluorite-perovskite biphase membranes possess both oxygen ion transport and electron conduction channels, making them promising candidates for use in CO2 decomposition membrane reactors. The elemental composition of the B-sites in the perovskite phase significantly influences the metal-oxygen bond strength, oxygen vacancy formation and migration behavior, reduction stability, and CO2 tolerance of the membrane substrate. Therefore, B-site doping to modulate the perovskite phase structure is a crucial strategy for enhancing the high-temperature stability and oxygen transport stability of the biphase membrane substrate. Furthermore, constructing porous functional layers on the membrane surface increases the surface reaction interface and improves surface exchange kinetics, playing a vital role in enhancing the performance of the membrane reactor.

[0004] However, existing research on oxygen-permeable membrane reactors mainly focuses on optimizing membrane substrate composition, improving CO2 corrosion resistance, or constructing a catalytic layer for partial methane oxidation on the permeate side, with insufficient attention paid to the surface reaction processes on the CO2 feed side. The CO2 feed side typically suffers from limited CO2 adsorption and activation capacity, insufficient oxygen vacancy-related active sites, low surface exchange rates, and the risk of carbonation under high-temperature CO2 atmospheres, limiting the CO2 decomposition rate and long-term operational stability. Therefore, a synergistic modification method for CO2 decomposition membrane reactors needs to be developed. This method could optimize membrane substrate stability through B-site doping and enhance surface exchange processes with A-site defect coatings on the CO2 feed side, thereby synergistically promoting CO2 adsorption and activation, oxygen species surface reactions, and transmembrane migration, ultimately improving the overall performance of the membrane reactor. Summary of the Invention

[0005] To address the problems of insufficient stability of the membrane substrate under high-temperature CO2 or reducing atmospheres, limited adsorption and activation capacity on the CO2 feed side, low surface exchange reaction rate, and limited long-term operational stability in existing oxygen-permeable membrane reactors during CO2 thermochemical decomposition, this invention proposes a synergistic modification method to improve the CO2 decomposition performance of ceramic membrane reactors. This invention improves the structural stability, oxygen transport stability, and reduction resistance of the dense membrane substrate by B-site doping of the perovskite phase in the fluorite-perovskite biphase membrane substrate. Simultaneously, an A-site defect perovskite porous coating is constructed on the CO2 feed side of the dense membrane substrate to enhance the adsorption and activation capacity and surface exchange reaction rate on the CO2 feed side. The synergistic effect of the B-site doped membrane substrate and the A-site defect porous coating promotes the generation, entry, and transmembrane migration of oxygen species generated during CO2 decomposition on the feed side, thereby enhancing the CO2 decomposition process in the membrane reactor.

[0006] This invention is achieved through the following technical solution: This invention proposes a synergistic modification method to improve the CO2 decomposition performance of ceramic membrane reactors, comprising the following steps: first, preparing a dense membrane substrate containing fluorite phase and B-site doped perovskite phase; subsequently, preparing A-site defect perovskite coating powder, wherein the A-site defect perovskite coating powder is (La 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ , where 0 < x <0.15; The A-site defect perovskite coating powder is then mixed with solvent, pore-forming agent and dispersant to obtain A-site defect perovskite coating slurry; The A-site defect perovskite coating slurry is then loaded onto the CO2 feed side of the dense membrane substrate; After heat treatment, an A-site defect perovskite porous coating is formed on the CO2 feed side of the dense membrane substrate, resulting in a membrane reactor with substrate-coating synergistic modification.

[0007] Furthermore, the dense film substrate is a fluorite-perovskite dual-phase film substrate, and the fluorite phase is Ce. 1- y Gd y O 2-δ , where 0 < y <0.5; The perovskite phase is a B-site doped perovskite phase.

[0008] Furthermore, the perovskite phase is Gd 0.1 Sr 0.9 Fe 1-z M z O 3-δ Or La 0.6 Sr 0.4 Fe 1-z Mz O 3-δ , where 0 < z <0.2, M is one or more of Al, Zr, Ti, Nb, and W.

[0009] Furthermore, the dense film substrate may be Ce. 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 Fe 1-z M z O 3-δ Two-phase film substrates are used to evaluate the effects of B-site doping (Al, Zr, Nb, W, etc.) on the structural stability of the substrate.

[0010] Furthermore, the dense film substrate may also be B-site doped with Ce. 0.8 Gd 0.2 O 2-δ -La 0.6 Sr 0.4 Fe 1-z M z O 3-δ The dense two-phase film substrate, M is one or more of Al, Zr, Ti, Nb, and W, preferably 60 wt.% Ce. 0.8 Gd 0.2 O 2-δ -40wt.%La 0.6 Sr 0.4 Fe 0.925 Ti 0.075 O 3-δ Two-phase membranes are used to construct CO2 decomposition membrane reactors modified with A-site defect coatings.

[0011] Furthermore, the thickness of the A-site defect perovskite porous coating is 5~30μm, and it has a continuous porous structure.

[0012] Furthermore, the A-site defect perovskite coating powder is synthesized by the sol-gel method and obtained by calcination at 750~1100℃ for 4~6 hours.

[0013] Furthermore, the solvent, pore-forming agent, and dispersant are terpineol, graphite powder, and polyethylene glycol, respectively, and the mass ratio of the A-site defect perovskite coating powder to terpineol is 1:1 to 1:10.

[0014] Furthermore, the A-site defect perovskite coating slurry is loaded onto the CO2 feed side of the dense film substrate by brushing, screen printing, spraying, dipping, spin coating, or scraping.

[0015] Furthermore, the heat treatment temperature is 800~1100℃, the heat treatment time is 0.5~10h, and the heat treatment is carried out in an air atmosphere.

[0016] Furthermore, the membrane reactor also includes Ce modified on the CH4 permeate side. 0.8 Gd 0.2 O 2-δ coating.

[0017] Furthermore, the membrane reactor obtained by the above-mentioned synergistic modification method comprises a dense membrane substrate containing a B-site doped perovskite phase, a porous perovskite coating with A-site defects modified on the CO2 feed side of the dense membrane substrate, and a Ce-modified coating on the CH4 permeate side. 0.8 Gd 0.2 O 2-δ coating.

[0018] This invention has the following substantial features and significant advantages: 1. This invention improves the structural stability and oxygen transport stability of dense film substrates under high temperature CO2 or reducing atmosphere by controlling the fluorite-perovskite dual-phase film substrate through B-site doping.

[0019] 2. The present invention constructs a porous perovskite coating with A-site defects on the CO2 feed side, which can increase the adsorption and activation sites of CO2 molecules and enhance the surface exchange reaction during the CO2 thermochemical decomposition process.

[0020] 3. This invention regulates (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ The concentration of A-site defects in the coating improves the chemical environment of defects on the coating surface, which is conducive to the generation of oxygen vacancies, surface exchange of oxygen species, and transmembrane migration.

[0021] 4. This invention combines a B-site doped film substrate with an A-site defect porous coating, which can simultaneously enhance the oxygen transport channels of the film substrate and the surface reaction process on the CO2 feed side, achieving a synergistic improvement in substrate stabilization and surface activation.

[0022] 5. The porous coating of the present invention has a continuous surface reaction interface, which can expand the effective reaction area on the CO2 feed side and improve the CO2 adsorption, activation and decomposition efficiency.

[0023] 6. The synergistic modified membrane reactor described in this invention can couple with the CH4 permeate side reaction to consume permeate oxygen, enhance the oxidation potential gradient across the membrane, thereby improving the CO2 decomposition rate and long-term operational stability.

[0024] 7. The process of this invention is simple and can be achieved using conventional powder synthesis, membrane substrate preparation, slurry preparation, surface loading and heat treatment processes. It has good repeatability and potential for scale-up applications. Attached Figure Description

[0026] Figure 1 For Ce 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 FeO 3-δ XRD patterns of its B-site doped Al, Zr, Nb, W biphase films.

[0027] Figure 2 For Ce 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 FeO 3-δ The XRD patterns of its B-site doped Al, Zr, Nb, W biphase films after 120 h of oxygen permeability testing under alternating Air / He and Air / CO2 gradients.

[0028] Figure 3 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ XRD pattern and magnified view of the coated powder.

[0029] Figure 4 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ BSEM-EDS image of the porous coating surface.

[0030] Figure 5 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ Cross-sectional BSEM-EDS image of a membrane reactor modified with porous coating.

[0031] Figure 6 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al0.1 O 3-δ O1sXPS plot of the coating.

[0032] Figure 7 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ CO2-TPD curve of the coating.

[0033] Figure 8 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ Porous coating modified membrane reactor in CO2 / CH4 gradient (CO2 flow rate 100 mL·min) -1 CO2 decomposition rate at different temperatures and corresponding Arrhenius curves.

[0034] Figure 9 At 900℃, different CO2 flow rates (La 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ A comparison of CO2 decomposition rate and CO2 conversion rate in a modified membrane reactor.

[0035] Figure 10 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ The modified membrane reactor was used in a CO2 / CH4 reactor (CO2 flow rate of 5 mL / min). -1 A comparison of long-term stability under gradient conditions.

[0036] Figure 11 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ XRD pattern of the feed-side coating surface after long-term stability testing of the modified membrane reactor.

[0037] Figure 12 For (La) 0.6 Sr 0.4 ) 1-x Fe 0.9 Al0.1 O 3-δ BSEM-EDS image of the feed-side coating surface after long-term stability testing of the modified membrane reactor. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0039] It should be noted that Example 1 is used to demonstrate the effect of B-site doping on improving the structural stability of the two-phase film substrate; Examples 2 and 3 are used to demonstrate the enhancement effect of constructing an A-site defect coating on a B-site Ti-doped GDC-LSF substrate on CO2 decomposition performance. The following examples are used together to illustrate the synergistic modification strategy of "substrate B-site doping stabilization" and "CO2 feed-side A-site defect coating activation" in this invention. Example

[0040] This embodiment illustrates the regulatory effect of B-site doping on the structural stability of fluorite-perovskite dual-phase film substrates. This embodiment uses Ce... 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 FeO 3-δ It is a two-phase film substrate, in which Ce 0.8 Gd 0.2 O 2-δ It is a fluorite phase, Gd 0.1 Sr 0.9 FeO 3-δ It is a perovskite phase. Through Gd... 0.1 Sr 0.9 FeO 3-δ Al, Zr, Nb, and W elements were introduced into the B-site of the perovskite phase to obtain B-site doped perovskite phase biphase film materials.

[0041] The B-site doped perovskite phase can be represented as Gd 0.1 Sr 0.9 Fe 1-z M z O 3-δ Where M is Al, Zr, Nb, or W, z =0.1. Ce was prepared using the sol-gel method. 0.8 Gd 0.2 O 2-δ Fluorite phase powder and B-site doped Gd 0.1 Sr 0.9 FeO 3-δ Perovskite phase powder was then mixed, shaped, and sintered at a certain mass ratio to obtain a dense two-phase film matrix containing B-site doped perovskite phase. Figure 1 ).

[0042] The obtained samples were subjected to alternating long-term stability evaluations under high-temperature Air / He and Air / CO2 gradients, respectively, and compared with undoped Ce. 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 FeO 3-δ 60wt.%Ce after doping with Al, Zr, Nb or W at the B site 0.8 Gd 0.2 O 2-δ -40wt.%Gd 0.1 Sr 0.9 Fe 0.9 M 0.1 O 3-δ Structural stability after testing Figure 2 ). Example

[0043] This embodiment provides a synergistic modification method to improve the CO2 decomposition performance of a ceramic membrane reactor. The synergistic modification method includes Ce 0.8 Gd 0.2 O 2-δ -La 0.6 Sr 0.4 Fe 1-z M z O 3-δ (The doping element M is Ti) Preparation of dense two-phase film substrate, construction of porous perovskite coating with A-site defects on the CO2 feed side, and Ce on the CH4 permeation side 0.8 Gd 0.2 O 2-δ The specific steps for constructing the coating are as follows: (1) Using an improved sol-gel method, and after calcination to form phases, (La) were obtained respectively. 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ Coating powder, Ce 0.8 Gd 0.2 O 2-δ Coating powder and 60 wt.% Ce 0.8 Gd 0.2 O 2-δ -40wt.%La 0.6 Sr 0.4 Fe 0.925 Ti 0.075 O 3-δ Membrane matrix powder.

[0044] (2) The obtained membrane matrix powder is mixed with 10wt.% paraffin, and after being dry-pressed at 150~250MPa for 2~3min, it is sintered at 1400℃ for 8~10h to obtain a dense biphase membrane matrix.

[0045] (3) (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ or Ce 0.8 Gd 0.2 O 2-δ The coating powder, terpineol, graphite powder, and polyethylene glycol were ball-milled at a mass ratio of 9%:90%:0.5%:0.5% for 24 hours to finally obtain (La 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ or Ce 0.8 Gd 0.2 O 2-δ Coating paste.

[0046] (4) The obtained (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ The coating slurry was brushed onto the CO2 feed side of the dense two-phase membrane substrate and calcined at 950°C for 2 hours.

[0047] (5) Ce 0.8 Gd 0.2 O 2-δ The coating slurry was brushed onto the CH4 permeation side of the dense membrane substrate and calcined at 950°C for 2 hours to obtain (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ (LS) 0.9 FA) coating modified two-phase oxygen-permeable membrane reactor.

[0048] The synthesized (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ The coating powder conforms to the target perovskite structure. Figure 3The structural stability is better than that of Comparative Example 2, and the prepared coating surface is porous and the thickness meets expectations. Figure 4 and Figure 5 ). Prepared (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ The coating-modified membrane reactor was placed in a self-made high-temperature furnace to test the CO2 decomposition rate at different temperatures and CO2 flow rates. Figure 8 and Figure 9 At 900℃, the feed rate is 5 mL / min. -1 CO2 concentration and osmotic pressure of 100 mL / min -1 Under conditions of 10% CH4 and 90% Ar, it can operate stably for 120 hours. Figure 10 In Example 2, the CO2 decomposition rate and stability under the above CO2 / CH4 gradient test conditions are consistently better than those of Comparative Example 1. Example

[0049] This embodiment is a parallel experiment with Embodiment 2, and the steps are basically the same. The difference is that: The CO2 feed-side coating powder prepared in step (1) is (La 0.6 Sr 0.4 ) 0.95 Fe 0.9 Al 0.1 O 3-δ (LS) 0.95 FA); In step (3), the powder is used to prepare the A-site defect coating slurry; In step (4), the slurry is brushed onto a dense 60wt.%Ce 0.8 Gd 0.2 O 2-δ -40wt.%La 0.6 Sr 0.4 Fe 0.925 Ti 0.075 O 3-δ CO2 feed side of the two-phase membrane substrate. Other membrane substrate preparation, Ce... 0.8 Gd 0.2 O 2-δ The coating preparation and heat treatment conditions were the same as in Example 2, resulting in (La) 0.6 Sr 0.4 ) 0.95 Fe 0.9 Al 0.1 O 3-δ Coating-modified two-phase oxygen-permeable membrane reactor.

[0050] Under the same CO2 / CH4 gradient test conditions, the CO2 decomposition rate and stability of Example 3 were consistently better than those of Comparative Example 1.

[0051] This comparative example was conducted in parallel with Example 2, and the steps were basically the same. The difference lies in: The CO2 feed-side coating is La without A-site defects. 0.6 Sr 0.4 Fe 0.9 Al 0.1 O 3-δ (LSFA) coating.

[0052] This comparative example was conducted in parallel with Example 2, and the steps were basically the same. The difference lies in: The CO2 feed-side coating is (La) 0.6 Sr 0.4 ) 0.85 Fe 0.9 Al 0.1 O 3-δ (LS) 0.85 FA coating.

[0053] Evaluation and Analysis of Test Experiment Results like Figure 1 As shown: Ce2 prepared in Example 1, both undoped and Al, Zr, Nb, W-doped at the B site. 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 Fe 0.9 M 0.1 O 3-δ The biphase film was subjected to XRD testing. As shown in the figure, the main diffraction peaks of the biphase film prepared in Example 1 are consistent, indicating that Ce... 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 Fe 0.9 M 0.1 O 3-δ A two-phase membrane was successfully prepared.

[0054] like Figure 2 As shown: Ce prepared in Example 1, both undoped and Al, Zr, Nb, W-doped at the B site. 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 Fe 0.9 M 0.1 O 3-δThe biphase membrane was first subjected to a long-term stability test of 120 h under Air / He and Air / CO2 gradients, followed by XRD analysis. As shown in the figure, the undoped Ce in Example 1... 0.8 Gd 0.2 O 2-δ -Gd 0.1 Sr 0.9 FeO 3-δ The biphase films exhibit a slight baseline rise above 35°, which may be related to local structural disorder, increased lattice microstrain, or trace amounts of secondary phases generated on the surface under long-term high-temperature CO2 atmosphere and oxidation potential gradient. In contrast, the diffraction peaks of the B-site doped biphase films are clearer and the baseline is more stable, indicating that B-site doping with Al, Zr, Nb, and W helps enhance the structural stability of the biphase film matrix under high-temperature CO2 and oxidation potential gradient.

[0055] like Figure 3 As shown: (La) used in Example 2, Example 3, Comparative Example 1, and Comparative Example 2 0.6 Sr 0.4 ) 1- x Fe 0.9 Al 0.1 O 3-δ The coated powder was subjected to XRD testing. As shown in the figure, the main diffraction peaks of the coated powders in Examples 2, 3 and Comparative Example 1 correspond to those of standard perovskite. However, in Comparative Example 2, the concentration of A-site defects was too high, and additional impurity phase peaks appeared in the sample. This indicates that only an appropriate amount of A-site defects can maintain the perovskite crystal structure, and an excessive concentration of A-site defects will affect the stability of the perovskite phase.

[0056] like Figure 4 As shown in the figure: BSEM-EDS tests were performed on the feed-side porous coating surfaces of Examples 2, 3, and Comparative Example 1. As can be seen from the figure, each coating exhibits a porous structure formed by particle accumulation, with a relatively continuous pore distribution, which is beneficial for enhancing the CO2 surface exchange reaction. Meanwhile, the EDS results show that the main elements in the coating are relatively uniformly distributed, indicating that the A-site defect coatings in Examples 2 and 3 have good chemical homogeneity.

[0057] like Figure 5 As shown: BSEM-EDS tests were performed on the cross-sections of the membrane reactors in Examples 2, 3, and Comparative Example 1. As can be seen from the figures, the porous coating on the feed side is continuously and tightly bonded to the membrane substrate surface, with a clear interface between the coating and the membrane substrate; no obvious cracks or peeling were observed. The elemental distribution diagrams show obvious delamination between the coating and the membrane substrate, indicating that the loading process of the A-site defect coating in Examples 2 and 3 did not damage the membrane substrate structure.

[0058] like Figure 6 As shown: O1s XPS tests were performed on the A-site defect coatings in Examples 2, 3, and Comparative Example 1. As can be seen from the figure, the O1s spectrum can be divided into lattice oxygen (O... lat ) and surface-adsorbed oxygen (O ad ) and other components. In Example 2 (La 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ Coating and in Example 3 (La) 0.6 Sr 0.4 ) 0.95 Fe 0.9 Al 0.1 O 3-δ O coating ad The proportions were 55.19% and 53.90%, both higher than La in the first comparative example. 0.6 Sr 0.4 Fe 0.9 Al 0.1 O 3-δ O coating ad The proportion (52.02%) indicates that A-site defects can increase the content of active oxygen species related to oxygen vacancies on the coating surface, thereby promoting CO2 adsorption activation and surface oxygen exchange processes.

[0059] like Figure 7 As shown: CO2-TPD tests were performed on the A-site defect coatings in Examples 2, 3, and Comparative Example 1. Compared with the peak temperature of the CO2 low-temperature desorption peak of the coating in Comparative Example 1 (110.5℃), the peak temperatures of the low-temperature desorption peak of the A-site defect coatings in Examples 2 and 3 were higher (115.2℃ and 113.9℃, respectively). Furthermore, the integral areas of the CO2 high-temperature desorption peak of the A-site defect coatings in Examples 2 and 3 were 432.65 and 348.04, respectively, which were larger than the 332.89 of Comparative Example 1. This indicates that an appropriate amount of A-site defects can improve the coating's adsorption capacity for CO2, providing more surface active sites for the thermochemical decomposition of CO2.

[0060] like Figure 8 As shown: the porous coating modified membrane reactors in Examples 2, 3, and Comparative Example 1 were subjected to a CO2 / CH4 gradient (100 mL / min on the feed side). -1 CO2, osmotic side 100 mL·min -1 Permeation tests were conducted at different temperatures using 10% CH4 and 90% Ar. At 925°C, the CO2 decomposition rates in Examples 2 and 3 were 1.52 mL·cm⁻¹, respectively. -2 ·min -1 and 1.21 mL·cm-2 ·min -1 All were higher than those of Comparative Example 1 (1.07 mL·cm⁻¹). -2 ·min -1 Of these, Example 2 exhibited the highest CO2 decomposition rate. Furthermore, in Example 2 (La... 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ The apparent activation energy of the coating-modified membrane reactor is 27.28 kJ·mol⁻¹. -1 This is far lower than the 49.70 kJ·mol⁻¹ of the membrane reactor in the comparative example. -1 This indicates that the A-site defect coating reduces the apparent activation energy of oxygen migration in the membrane reactor.

[0061] like Figure 9 As shown: The CO2 decomposition performance of the membrane reactors in Examples 2, 3, and Comparative Example 1 was tested at 900°C and different CO2 flow rates (permeate side: 100 mL·min). -1 (10% CH4 and 90% Ar). In Example 2 (La) 0.6 Sr 0.4 ) 0.9 Fe 0.9 Al 0.1 O 3-δ And in Example 3 (La) 0.6 Sr 0.4 ) 0.95 Fe 0.9 Al 0.1 O 3-δ The CO2 decomposition rate of the modified membrane reactor at a CO2 flow rate of 40 mL·min -1 and 60 mL·min -1 The membrane reactor in Comparative Example 1 reached its maximum value at 80 mL / min. -1 Only then did it reach its maximum value. At the same CO2 flow rate, the CO2 decomposition rate and conversion rate of the membrane reactors in Examples 2 and 3 were better than those in Comparative Example 1, indicating that the A-site defect coating enhanced the CO2 surface exchange reaction on the feed side.

[0062] like Figure 10 As shown: The membrane reactors in Examples 2, 3, and 1 were tested at 900°C with a CO2 / CH4 gradient (5 mL / min on the feed side). -1 CO2, osmotic side 100 mL·min -1Long-term stability tests were conducted using membrane reactors containing 10% CH4 and 90% Ar. After long-term operation, the CO2 decomposition rates of the membrane reactors in Examples 2 and 3 were 1.15 mL·cm⁻¹, respectively. -2 ·min -1 and 0.74 mL·cm -2 ·min -1 Comparative Example 1 was 0.53 mL·cm⁻¹ -2 ·min -1 Furthermore, the performance degradation rates of the three were 10%, 9.8%, and 14.5%, respectively, indicating that a reasonable A-site defect concentration is beneficial to improving the long-term operational stability of the membrane reactor.

[0063] like Figure 11 As shown: XRD tests were performed on the feed-side coating surfaces of the membrane reactors in Examples 2, 3, and Comparative Example 1 after long-term stability testing. In Comparative Example 1, La... 0.6 Sr 0.4 Fe 0.9 Al 0.1 O 3-δ SrCO3-related diffraction peaks were observed on the coating surface, while the formation of the carbonate phase was suppressed in Examples 2 and 3, indicating that A-site defects are beneficial to improving the CO2 tolerance of the coating.

[0064] like Figure 12 As shown: BSEM-EDS tests were performed on the feed-side coating surfaces of the membrane reactors in Examples 2, 3, and Comparative Example 1 after long-term stability testing. The coatings in Examples 2 and 3 maintained a porous particle packing structure after the reaction, without significant cracking, peeling, or structural collapse, and the degree of sintering was less than in Comparative Example 1. EDS results showed that the main elements remained relatively uniformly distributed, indicating that the A-site defect porous coatings in Examples 2 and 3 possessed good morphological and interfacial stability.

[0065] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make various modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be included within the scope of protection defined by the claims.

Claims

1. A synergistic modification method for improving the CO2 decomposition performance of a ceramic membrane reactor, characterized in that, Includes the following steps: (1) Prepare a dense film substrate containing fluorite phase and B-site doped perovskite phase; (2) Prepare A-site defect perovskite coating powder, wherein the A-site defect perovskite coating powder is (La 0.6 Sr 0.4 ) 1-x Fe 0.9 Al 0.1 O 3-δ , where 0 < x <0.15; (3) Mix the A-site defect perovskite coating powder with solvent, pore-forming agent and dispersant to obtain A-site defect perovskite coating slurry; (4) Load the A-site defect perovskite coating slurry onto the CO2 feed side of the dense membrane substrate; (5) After heat treatment, form an A-site defect perovskite porous coating on the CO2 feed side of the dense membrane substrate to obtain a membrane reactor with substrate-coating synergistic modification.

2. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The dense film substrate is a fluorite-perovskite biphase film substrate, and the fluorite phase is Ce. 1-y Gd y O 2-δ , where 0 < y <0.5; The perovskite phase is a B-site doped perovskite phase.

3. The method for synergistic modification of membrane reactors according to claim 2, characterized in that, The perovskite phase is Gd 0.1 Sr 0.9 Fe 1-z M z O 3-δ Or La 0.6 Sr 0.4 Fe 1-z M z O 3-δ , where 0 < z < 0.

2.

4. The method for synergistic modification of membrane reactors according to claim 3, characterized in that, The doping element M used in the perovskite phase is one or more of Al, Zr, Ti, Nb, and W.

5. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The thickness of the A-site defect perovskite porous coating is 5~30μm and it has a continuous porous structure. The A-site defect perovskite coating powder is synthesized by sol-gel method and obtained by calcination at 750~1100℃ for 4~6h.

6. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The solvent, pore-forming agent, and dispersant are terpineol, graphite powder, and polyethylene glycol, respectively, and the mass ratio of the A-site defect perovskite coating powder to terpineol is 1:1 to 1:

10.

7. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The A-site defect perovskite coating slurry is applied to the CO2 feed side of the dense film substrate by brushing, screen printing, spraying, dipping, spin coating, or scraping.

8. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The heat treatment temperature is 800~1100℃, the heat treatment time is 0.5~10h, and the heat treatment is carried out in an air atmosphere.

9. The method for synergistic modification of membrane reactors according to claim 1, characterized in that, The membrane reactor also includes Ce modified on the CH4 permeate side. 0.8 Gd 0.2 O 2-δ coating.

10. A membrane reactor obtained by the synergistic modification method according to any one of claims 1-10, characterized in that, The membrane includes a dense film substrate containing a B-site doped perovskite phase, a porous perovskite coating with A-site defects modified on the CO2 feed side of the dense film substrate, and a Ce-doped coating modified on the CH4 permeation side. 0.8 Gd 0.2 O 2-δ coating.

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