A solid solution catalyst, its preparation method and application

Abstract

This invention relates to the field of catalyst technology, specifically to a solid solution catalyst, a method for preparing the solid solution catalyst, the application of the solid solution catalyst in the nitrous oxide reduction-coupling reaction with methane oxidation, and a method for regulating the solid solution catalyst in catalyzing the nitrous oxide reduction-coupling reaction with methane oxidation. The solid solution catalyst comprises a Gd₂O₃ lattice matrix and Sm₂ located in the Gd₂O₃ lattice matrix. 3+ Solid solution catalysts include Gd 3+ and Sm 3+ Gd in solid solution catalyst 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage A is 0.5% ≤ A < 50%. The solid solution catalyst of this invention can improve the matching degree between the oxygen species release rate and the methane activation rate, break the seesaw bottleneck between coupling reaction activity and C2 selectivity, and improve C2 yield and alkene-alkane ratio.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a solid solution catalyst, a method for preparing the solid solution catalyst, the application of the solid solution catalyst in the nitrous oxide reduction-methane oxidative coupling reaction, and a method for regulating the solid solution catalyst in catalyzing the nitrous oxide reduction-methane oxidative coupling reaction. Background Technology

[0002] Methane, as a crucial component of natural gas, shale gas, and various industrial and biological processes, possesses high chemical stability, and its direct high-value conversion has always been an important research direction in the field of catalysis. Oxidative coupling of methane (OCM) is a potential technological route that can directly convert CH4 into C2 hydrocarbons (ethane and ethylene). Ethylene is one of the most important raw materials in the basic chemical industry, traditionally obtained mainly through steam cracking of petroleum-based feedstocks, which is energy-intensive and produces significant carbon emissions.

[0003] Most existing OCM technologies use molecular oxygen (O2) as the oxidant (i.e., O2-OCM). These systems typically require temperatures above 700°C to activate methane, and the reaction process is highly susceptible to deep oxidation of methane and intermediates, generating CO and CO2, resulting in low C2 selectivity. Furthermore, the high temperature and strong oxidizing environment easily induce catalyst sintering and structural instability, limiting the industrial application prospects of this technology. Summary of the Invention

[0004] Nitrous oxide (N₂O) and methane (CH₄) are both non-carbon dioxide greenhouse gases with significant greenhouse effects. N₂O, in particular, has an extremely high global warming potential and a long atmospheric lifetime, and is also one of the most potent ozone-depleting substances known. Industrial production processes, especially in chemical processes involving adipic acid and caprolactam, can result in concentrated emissions of N₂O at concentrations ranging from 10% to 40% by volume. Current engineering methods for controlling these emissions primarily employ direct catalytic decomposition or selective catalytic reduction, but these methods typically only achieve harmless treatment and fail to utilize N₂O as an oxygen source or reactant for resource recovery. Utilizing N₂O as a "mild oxygen source" to drive the methane oxidative coupling reaction (N₂O-OCM) offers the potential of a solution. Compared to O₂, N₂O has lower oxidative activity, and its decomposition can generate reactive oxygen species with a certain degree of reaction selectivity, theoretically helping to lower the reaction temperature and inhibit deep oxidation. However, existing catalyst systems struggle to simultaneously achieve high N₂O activation efficiency and high C₂ selectivity.

[0005] Studies have revealed that in the methane oxidative coupling reaction system using N2O as the oxidant, the reaction process involves multiple consecutive reaction steps, including the activation and decomposition of N2O, the generation and migration of reactive oxygen species, the initial activation of CH4, and the generation and desorption of C2 intermediates. When the concentration of reactive oxygen species is too high, CH4 and the already generated two-carbon intermediates are prone to further deep oxidation reactions, converting into CO and CO2, directly leading to a decrease in the selectivity of the target C2 hydrocarbons (ethane and ethylene). Therefore, the N2O-OCM reaction system has high requirements for catalyst structure and oxygen species regulation capabilities. Existing technologies generally suffer from a seesaw bottleneck problem—a significant decrease in C2 selectivity as CH4 conversion increases. This makes it difficult to overcome the long-standing activity-selectivity constraint in the methane oxidative coupling reaction. Currently used single rare earth oxide catalyst systems and mechanically mixed or supported catalysts of multi-metal oxides are all difficult to form an effective synergistic regulation relationship among the above-mentioned multiple reaction steps, resulting in significant technical defects during the reaction process.

[0006] Specifically, single rare earth oxide catalysts (e.g., Gd2O3, Sm2O3, La2O3, etc.) can be used for N2O decomposition or CH4 activation reactions under high temperature conditions. These catalysts are usually single metal oxide phases and have a certain oxygen migration ability. However, in the N2O-OCM system, the following problems often exist: (1) The coupling degree between N2O decomposition and CH4 oxidation processes is low, and active oxygen species are difficult to be effectively controlled; (2) It is easy to induce complete oxidation of methane, resulting in low selectivity of C2 products; (3) The reaction temperature is still high, making it difficult to break through the energy consumption bottleneck of traditional OCM.

[0007] To improve the catalytic performance of single rare earth oxide catalysts, existing technologies employ methods such as combining different rare earth oxides through mechanical mixing (i.e., multi-metal oxide mechanically mixed catalysts) or loading one metal oxide onto the surface of another oxide (i.e., supported catalysts) to introduce synergistic effects from multiple active sites. However, the preparation of multi-metal oxide mechanically mixed or supported catalysts typically involves the following steps: (1) preparing different metal oxides separately; (2) forming a composite catalyst through physical mixing, impregnation, or loading; and (3) using it for reaction after high-temperature calcination. However, since different metal components are independent at the crystal structure level, the spatial separation between active sites is obvious, and the generated active oxygen species are easily enriched in local areas. Their release rate and reaction timing are difficult to control precisely, making it difficult to accurately match the oxygen species release rate with the methane activation rate. Problems such as low C2 selectivity and insufficient stability still exist. Furthermore, in existing multi-metal oxide catalyst systems constructed through mechanical mixing or loading, the different metal oxide components are usually in physical contact, lacking a unified and continuous crystal structure. Since the components are separated from each other at the microscale, the spatial distance and interaction between the N2O activation center and the CH4 activation center are difficult to control. As a result, oxygen species cannot be efficiently and directionally used for the selective activation of CH4 after generation, but are more likely to participate in non-selective oxidation reactions, thus limiting the further improvement of C2 product yield.

[0008] Meanwhile, due to the lack of effective buffering mechanisms for the generation and consumption of reactive oxygen species in existing catalysts, the reaction usually needs to be carried out at higher temperatures to achieve a considerable CH4 conversion rate. High-temperature operation not only increases the energy consumption of the N2O-OCM reaction system but also further exacerbates the tendency for complete oxidation of CH4, making deep oxidation side reactions more significant. In addition, under high-temperature conditions, catalyst particles are prone to sintering and grain growth, reducing the number of active sites and causing the catalyst performance to gradually decline with prolonged operation, thereby affecting the stability and sustainable operation capability of the N2O-OCM reaction.

[0009] To address the problem in the N2O-OCM reaction where existing catalysts fail to achieve a low match between oxide release rate and methane activation rate, resulting in increased CH4 conversion but decreased C2 selectivity, this invention provides a solid solution catalyst, a method for preparing the solid solution catalyst, the application of the solid solution catalyst in the nitrous oxide reduction-methane oxidative coupling reaction, and a method for regulating the solid solution catalyst in catalyzing the nitrous oxide reduction-methane oxidative coupling reaction. The solid solution catalyst of this invention can improve the match between oxide release rate and methane activation rate, balancing CH4 activity and C2 selectivity, thereby increasing C2 yield, methane single-pass conversion, and alkene-to-alkane ratio.

[0010] To achieve the above objectives, a first aspect of the present invention provides a solid solution catalyst, wherein the solid solution catalyst comprises a Gd₂O₃ lattice matrix and Sm₂ located in the Gd₂O₃ lattice matrix. 3+ The solid solution catalyst includes Gd 3+ and Sm 3+ Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage A is 0.5% ≤ A < 50%.

[0011] A second aspect of the present invention provides a method for preparing a solid solution catalyst, wherein the solid solution catalyst prepared by the method is the solid solution catalyst described in the first aspect of the present invention, wherein the preparation method includes: S1: Mix the soluble metal salt of Sm, the soluble metal salt of Gd, and water to form the first solution; S2: The first solution and the precipitant undergo a first contact, and a precipitate is obtained through solid-liquid separation; S3: The precipitate is roasted.

[0012] The third aspect of the present invention provides a nitrous oxide reduction-synergistic methane oxidative coupling reaction, wherein the methane oxidative coupling reaction is a chemical reaction in which nitrous oxide provides an oxygen source and methane is oxidized to produce ethane and / or ethylene, and the catalyst for the methane oxidative coupling reaction is the solid solution catalyst described in the first aspect of the present invention and / or the solid solution catalyst prepared by the preparation method described in the second aspect of the present invention.

[0013] The fourth aspect of this invention provides a method for regulating the catalytic coupling reaction of nitrous oxide reduction and methane oxidation using a solid solution catalyst. The solid solution catalyst is the solid solution catalyst described in the first aspect of this invention and / or a solid solution catalyst prepared by the preparation method described in the second aspect of this invention. The nitrous oxide reduction and methane oxidation coupling reaction is the coupling reaction described in the third aspect of this invention. The method for regulating the catalytic coupling reaction of nitrous oxide reduction and methane oxidation using a solid solution catalyst satisfies the following relationship: 3 ≤ B / (A×S) ≤ 200, where B is the molar flow rate of the nitrous oxide in mol / h; A is the molar flow rate of Gd in the solid solution catalyst. 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage; S is the total molar amount of the solid solution catalyst used, in mol.

[0014] By employing the above technical solution, the present invention has at least the following advantages compared with the prior art: This invention utilizes the isovalent solid solution of Sm in the lattice of Gd₂O₃. 3+ Constructing SmGdO x A solid solution catalyst achieves synergistic optimization of functional sites within the catalyst, while simultaneously controlling the amount of Gd in the solid solution catalyst. 3+ and Sm 3+ The total sum of moles is used as the benchmark Sm 3+ The molar percentage of oxygen species in Gd₂O₃ lattice-regulated slow-release properties and Sm 3+ The synergistic effect of methane activation enables efficient conversion of N2O and CH4 during the reaction, thereby improving C2 yield, methane single-pass conversion rate, and alkene-alkane ratio.

[0015] Other features and advantages of the present invention will be described in detail in the following detailed description section.

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Attached Figure Description

[0017] Figure 1 The diagram shown is a schematic representation of the crystal structure of Gd₂O₃ in the prior art (where green represents Gd). 3+ Red represents O 2- ).

[0018] Figure 2 The diagram shown is a schematic representation of the cell structure of the solid solution catalyst of the present invention (wherein, green represents Gd). 3+ Blue represents Sm 3+ Red represents O 2- ).

[0019] Figure 3 The image shown is a SEM image of the solid solution catalyst of the present invention.

[0020] Figure 4 The figure shows the different Sm values ​​of the present invention. 3+ XRD patterns of solid solution catalysts with a molar percentage of .

[0021] Figure 5 As shown Figure 4 A magnified view of A in the middle. Detailed Implementation

[0022] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. Unless otherwise specified herein, data ranges include endpoints.

[0023] It should be noted that the numerical designations such as "first" and "second" in this invention are only used to distinguish different substances or methods of use, and do not represent a difference in order.

[0024] A first aspect of the present invention provides a solid solution catalyst, wherein the solid solution catalyst comprises a Gd₂O₃ lattice matrix and Sm₂ located in the Gd₂O₃ lattice matrix. 3+ The solid solution catalyst includes Gd 3+ and Sm 3+ Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage A is 0.5% ≤ A < 50% (e.g., 0.5%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 33%, 35%, 38%, 40%, 42%, 44%, 45%, 48%, 49%, or within any two of the above values).

[0025] In this invention, Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage can be obtained by ICP-OES testing. Specifically: accurately weigh 10.00 mg of the solid solution catalyst sample into 2 mL-4 mL of digestion solution (concentrated nitric acid) and 0.2 mL-0.5 mL of hydrofluoric acid (HF). Place the digestion container in a microwave digestion apparatus, heat to 180℃-200℃ and maintain for 30 min-60 min, or place it on a hot plate and heat at 160℃-180℃ for 4 h-8 h until the solid solution catalyst sample is completely digested, obtaining a clear and transparent digestion solution. Dilute to a volume that matches the standard curve of the ICP-OES (Inductively Coupled Plasma Atomic Emission Spectrometry) instrument, calculate the mass percentage, and thus obtain the molar percentage of Gd in the solid solution catalyst. 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentages are as follows: Concentrated nitric acid (HNO3) has a mass content of 65 wt%-68 wt%, and hydrofluoric acid (HF) has a mass content of 40 wt%. like Figure 1 This is a schematic diagram of the cell structure of Gd2O3 in the prior art. Figure 2 This is a schematic diagram of the cell structure of the solid solution catalyst of the present invention. Figure 2 As can be seen from the diagram, in the unit cell of the solid solution catalyst of the present invention, Gd 3+ and Sm 3+ Existing in the same crystal lattice, through Figure 1 and Figure 2 The comparison shows that in the solid solution catalyst of the present invention, some Gd 3+ Sm 3+ Equivalent substitution, which enables Sm 3+ Distributed within the cell structure of Gd2O3 without introducing additional charge to compensate for defects, this allows for the regulation of the local environment of the metal-oxygen bonds while maintaining the structural stability of the solid solution catalyst. This enables the formation of reaction sites on the surface of the solid solution catalyst suitable for selective activation by N2O, thereby allowing the solid solution catalyst structure to generate surface-active oxygen species in a controlled manner during the N2O-OCM reaction. It also reduces or even avoids the instantaneous enrichment of oxygen species in local areas, thereby reducing the probability of deep oxidation of CH4 and its reaction intermediates at the structural level.

[0026] like Figure 3 The image shown is a SEM image of the solid solution catalyst of the present invention. In the solid solution catalyst of the present invention, the Gd₂O₃ lattice regulates the oxidation capacity of the reaction by slow-releasing surface oxygen species, preventing the excessive oxidation of methane and two-carbon intermediates caused by the instantaneous enrichment of active oxygen. 3+ Primarily responsible for the activation and coupling reactions of methane, enabling the efficient formation of ethylene and ethane from the methyl intermediate; this invention utilizes the isovalent solid solution of Sm in the Gd₂O₃ lattice. 3+ Constructing SmGdO x The solid solution catalyst achieves synergistic optimization of functional sites in the catalyst. Through this bifunctional synergistic strategy, the catalyst can achieve high two-carbon product selectivity and stable alkene-alkane ratio at a lower reaction temperature, thereby improving the problem in the existing technology that it is difficult to balance CH4 activity and C2 selectivity in the N2O-OCM reaction.

[0027] Furthermore, the present invention also controls the amount of Gd in the solid solution catalyst. 3+ and Sm 3+ The total sum of moles is used as the benchmark Sm 3+ The molar percentage of Sm 3+ Gd₂O₃ and Sm₂O₃ are uniformly distributed in the crystal lattice, forming a more stable solid solution structure. The slow-release properties of oxygen species regulated by the Gd₂O₃ lattice are similar to those of Sm₂O₃. 3+The synergistic effect of the methane activation capability enables efficient conversion of N2O and CH4 during the reaction, thereby improving C2 yield, methane single-pass conversion rate, and alkene-to-alkane ratio. Furthermore, the solid solution catalyst of this invention can improve reaction efficiency while maintaining environmental friendliness, demonstrating high potential for industrial application.

[0028] In this invention, Sm is introduced into Gd2O3. 3+ , making Sm 3+ Equivalent replacement of part of Gd 3+ Simultaneously controlling the amount of Gd in the solid solution catalyst 3+ and Sm 3+ The total sum of moles is used as the benchmark Sm 3+ Compared with existing technologies, the molar ratio of this catalyst has improved the problem of low matching between oxide release rate and methane activation rate in the N2O-OCM reaction, thus increasing the matching degree between oxide release rate and methane activation rate, and improving C2 yield, methane single-pass conversion, and alkene-alkane ratio. To further improve the effect, one or more of these technical features can be further optimized.

[0029] In some instances, Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total moles, Sm 3+ The molar percentage A is 20% ≤ A ≤ 45%.

[0030] In some instances, in the solid solution catalyst, Gd 3+ and Sm 3+ The sum of total moles and O 2- The molar ratio is (1.9-2.1):(2.9-3.1) (e.g., 1.9:2.9, 1.9:3, 1.9:3.1, 2:2.9, 2:3, 2:3.1, 2.1:2.9, 2.1:3, 2.1:3.1, or within any two of the above values). When Gd is in the solid solution catalyst... 3+ and Sm 3+ The sum of total moles and O 2- When the molar ratio of Gd satisfies the above range, it indicates that in the solid solution catalyst, Gd... 3+ and Sm 3+ The sum of total moles and O 2- The molar ratio of Sm remains essentially constant at around 2:3, further illustrating that Sm 3+ The substitution is equivalent substitution, and the solid solution catalyst formed is a metal oxide solid solution with a single crystal phase structure.

[0031] In some instances, the 2θ of the peak value of the 222 plane diffraction peak in the XRD pattern of the solid solution catalyst is 28.42°–28.69° (e.g., 28.42°, 28.45°, 28.48°, 28.5°, 28.53°, 28.55°, 28.58°, 28.6°, 28.63°, 28.65°, 28.69°, or within any two of these values). In the XRD pattern of the solid solution catalyst, as shown... Figure 4 As shown, the peak value of the 222 crystal plane diffraction peak is 28.42°-28.67°, that is, the 222 crystal plane diffraction peak exists in the range of 2θ of 28.42°-28.67°, indicating that Gd2O3 exists in the solid solution catalyst of the present invention.

[0032] In some instances, the XRD patterns of the solid solution catalysts do not exhibit a 222 diffraction peak in the range of 2θ between 28.12° and 28.4° (e.g., 28.12°, 28.15°, 28.17°, 28.2°, 28.22°, 28.25°, 28.27°, 28.3°, 28.32°, 28.35°, 28.37°, 28.4°, or any combination of the above values). Figure 4 As shown, this indicates that there is no independent Sm2O3 phase in the solid solution catalyst of the present invention.

[0033] In this invention, the XRD pattern of the solid solution catalyst is tested under the following conditions: copper target (Cu Kα) and X-ray wavelength of 1.5406 Å.

[0034] In some instances, the solid solution catalyst does not include an independent Sm2O3 phase.

[0035] In some instances, the solid solution catalyst comprises a Gd₂O₃ lattice and does not include an independent Sm₂O₃ phase. This indicates that the solid solution catalyst is a single-phase solid solution, thereby ensuring the stability of the crystal structure of the solid solution catalyst and forming highly active catalytic sites.

[0036] In some instances, the solid solution catalyst is a binary metal oxide of Gd and Sm, i.e., the solid solution catalyst is composed of Gd... 3+ 、Sm 3+ and O 2- composition.

[0037] In some instances, the solid solution catalyst further includes a first metal selected from one or more of alkali metals, alkaline earth metals, transition metals, rare earth metals, noble metals, and p-block metals. The aforementioned first element helps to regulate the surface reaction site properties and oxygen species behavior of the solid solution catalyst's catalytic system, thereby promoting the improvement of N2O-OCM reaction performance.

[0038] In some instances, the alkali metal is selected from one or more of Na, K, and Cs. The alkali metal can provide a strongly basic site and can also promote the formation of methyl radicals from methane, thereby further enhancing the catalytic performance of the solid solution catalyst.

[0039] In some instances, the alkaline earth metal is selected from one or more of Mg, Ca, Sr, and Ba. The alkaline earth metal element can modulate the basicity of the solid solution catalyst, stabilize its crystal structure, and optimize the formation of oxygen vacancies, thereby further enhancing the catalytic performance of the solid solution catalyst.

[0040] In some instances, the transition metal is selected from one or more of Fe, Co, Ni, Cu, and Mn. The transition metal has a variable valence state, enabling it to construct redox active centers and enhance the decomposition and activation of N₂O, thereby further improving the catalytic performance of the solid solution catalyst.

[0041] In some instances, the rare earth metal is selected from one or more of La, Ce, Pr, Tb, and Y. The rare earth metal can modulate oxygen storage and release capacity, improve oxygen migration performance, and stabilize the catalytic structure, thereby further enhancing the catalytic performance of the solid solution catalyst.

[0042] In some instances, the noble metal is selected from one or more of Ir, Pt, Pd, and Ru. The noble metal can promote the breaking of NO bonds and the transfer of electrons, thereby further enhancing the catalytic performance of the solid solution catalyst.

[0043] In some instances, the p-block metal is selected from one or more of Sn, In, Bi, and Ge. The p-block metal can suppress excessive oxidation of the product, thereby further enhancing the catalytic performance of the solid solution catalyst.

[0044] In some instances, the first element exists in the solid solution catalyst in a doping or mechanically mixed manner.

[0045] In some instances, the weight percentage of the first metal is 0%-2% based on the total weight of the solid solution catalyst (e.g., 0%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8%, 2%, or any two of the above values). When the weight percentage of the first metal is 0% based on the total weight of the solid solution catalyst, it indicates that the first metal is not present in the solid solution catalyst.

[0046] When the weight percentage of the first metal is greater than 2% based on the total weight of the solid solution catalyst, it will lead to an increase in side reactions, such as methane reforming (H2 / CO) or deep oxidation of methane (CO2 / H2O), which is not conducive to improving C2 selectivity.

[0047] In this invention, the weight percentage of the first metal, based on the total weight of the solid solution catalyst, can be obtained by ICP-OES testing. The specific method can be found in the section on "the weight percentage of the first metal based on the total weight of the solid solution catalyst (Gd)". 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The test method is "molar percentage".

[0048] A second aspect of the present invention provides a method for preparing a solid solution catalyst, wherein the solid solution catalyst prepared by the method is the solid solution catalyst described in the first aspect of the present invention, wherein the preparation method includes: S1: Mix the soluble metal salt of Sm, the soluble metal salt of Gd, and water to form the first solution; S2: The first solution and the precipitant undergo a first contact, and a precipitate is obtained through solid-liquid separation; S3: The precipitate is roasted.

[0049] In some instances, in step S1, the first solution is a homogeneous mixture of metal ions, causing Sm 3+ and Gd 3+Sufficient dispersion at the solution scale. During the formation of the first solution, simultaneous sonication and stirring can further improve its homogeneity. The sonication conditions include: a frequency of 20kHz-50kHz (e.g., 20kHz, 25kHz, 30kHz, 35kHz, 40kHz, 45kHz, 50kHz, or any two of these values), and a time of 10min-60min (e.g., 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, or any two of these values); the stirring conditions include: a temperature of 40℃-80℃ (e.g., 40℃, ...). Temperatures of 45℃, 50℃, 60℃, 65℃, 70℃, 75℃, 80℃ or within any two of the above values, with a rotation speed of 500rpm-700rpm (e.g., 500rpm, 530rpm, 550rpm, 580rpm, 600rpm, 630rpm, 650rpm, 680rpm, 700rpm or within any two of the above values), and a time of 1h-3h (e.g., 1h, 1.3h, 1.5h, 1.8h, 2h, 2.3h, 2.5h, 2.8h, 3h or within any two of the above values).

[0050] In some instances, during step S3, the precipitate crystallizes under calcination and forms a structurally stable solid solution catalyst.

[0051] In some instances, the soluble metal salt of Sm is selected from one or more of samarium nitrate, samarium acetate, samarium halide, and samarium sulfate.

[0052] In some instances, the soluble metal salt of the Gd is selected from one or more of gadolinium nitrate, gadolinium acetate, gadolinium halide, and gadolinium sulfate.

[0053] In some instances, the precipitant is selected from one or more of ammonia, urea, ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide.

[0054] In some instances, the molar ratio X of the soluble metal salt of Sm to the soluble metal salt of Gd is 0.005 ≤ X < 1 (e.g., 0.005, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, or within any two of the above values).

[0055] In some instances, the molar ratio X of the soluble metal salt of Sm to the soluble metal salt of Gd is 0.25 ≤ X ≤ 0.82.

[0056] In some instances, the conditions for the first contact include: a temperature of 20°C-90°C (e.g., 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or any two of the above values), and a pH of 8-13 (e.g., 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, or any two of the above values). The pH value of the first contact can be achieved through continuous or stepwise adjustment, so that Sm... 3+ and Gd 3+ The precipitation reaction occurs simultaneously, thus avoiding the presence of two phases in the precipitate due to the difference in precipitation kinetics between the two metal ions.

[0057] In some instances, the calcination conditions include: a temperature of 600°C-1000°C (e.g., 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, or any combination of the above values), a time of 2h-24h (e.g., 2h, 4h, 6h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, or any combination of the above values), and a calcination atmosphere selected from one or more of air, oxygen, and nitrogen. By controlling the above calcination conditions, Sm can be... 3+ It is uniformly dissolved in the Gd2O3 lattice without forming an independent Sm2O3 phase, and can also form stable oxygen vacancies. These oxygen vacancies can activate N2O in the methane oxidative coupling reaction to generate active oxygen species with slow-release characteristics.

[0058] In some instances, the total concentration of metal ions in the first solution is 0.01 mol / L to 1 mol / L (e.g., 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, or within any two of the above values).

[0059] In some instances, prior to step S3, the precipitate is further aged, washed, and dried. Aging and washing remove residual ions and impurities. It is understood that residual ions and impurities include one or more of the following: acid radical anions from soluble metal salts of Sm, acid radical anions from soluble metal salts of Gd, and ions from the precipitant.

[0060] In some instances, the aging conditions include: a temperature of 50°C-90°C (e.g., 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or any two of the above values), and a time of 0.5h-6h (e.g., 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, or any two of the above values).

[0061] In some instances, the washing conditions include: the washing solution being selected from one or more of deionized water, ethanol, and methanol, and washing until the pH of the supernatant is 7-8 (e.g., 7, 7.3, 7.5, 7.8, 8, or within any two of the above values).

[0062] In some instances, the drying conditions include a temperature of 60°C to 140°C (e.g., 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or within any two of the above values) and a time of 8h to 24h (e.g., 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or within any two of the above values).

[0063] The method for preparing the solid solution catalyst of the present invention can prepare the solid solution catalyst described in the first aspect of the present invention. The method for preparing the solid solution catalyst of the present invention not only forms a uniform crystal phase structure, but also avoids the problem of uneven active sites during mechanical mixing and impregnation methods, thus ensuring the catalytic performance of the prepared solid solution catalyst.

[0064] The third aspect of the present invention provides a nitrous oxide reduction-coupling reaction with methane oxidation, wherein the coupling reaction is a chemical reaction in which nitrous oxide provides an oxygen source and methane is oxidized to produce ethane and / or ethylene, and the catalyst for the coupling reaction is the solid solution catalyst described in the first aspect of the present invention and / or the solid solution catalyst prepared by the preparation method described in the second aspect of the present invention.

[0065] The reaction process of the coupling reaction is as follows: (1) Methane molecules on the surface of the solid solution catalyst Sm 3+ CH bonds break at the site, generating surface-adsorbed methyl groups and surface-active hydrogen species. CH4(g)+ →CH3 +H , Represented as Sm surface active sites, H Represented as an active hydrogen species; (2) Adsorbed methyl groups desorb to gaseous methyl radicals. CH3 →CH3·, CH3· represents a methyl radical; (3) Highly reactive methyl radicals in the gas phase couple to form ethane. 2CH3·→CH3CH3 (4) Ethane undergoes CH bond activation on the surface of a solid solution catalyst, resulting in dehydrogenation to ethylene, and simultaneously generating active hydrogen species (H). ) CH3CH3+ →CH2CH2+2H H Represented as an active hydrogen species; (5) N2O molecules adsorbed on oxygen vacancies on the surface of the solid solution catalyst undergo NO bond breakage and decompose into N2 (gas phase desorption) and adsorbed active oxygen species; due to the slow-release characteristics of Gd2O3, these oxygen species can reduce / avoid excessive oxidation of carbon-containing intermediates. N2O+O v →N2(g)+O O v Represented as oxygen vacancy, O Reactive oxygen species to fill oxygen vacancies; (6) The H generated above With O It combines to generate water, consumes the generated active hydrogen species, releases active sites, and regenerates oxygen vacancies.

[0066] 2H +O →H2O+O v The solid solution catalyst of the present invention is applied to the nitrous oxide reduction-coordinated methane oxidative coupling reaction, wherein the Sm in the solid solution catalyst... 3+ The solid solution catalyst can control the activation of methane and promote coupling reactions. The Gd₂O₃ lattice in the catalyst can control the slow release of active oxygen species generated from N₂O. The Sm₂ in the solid solution catalyst... 3+ In synergy with the Gd2O3 lattice, it can improve the matching degree between the oxide species release rate and the methane activation rate, thereby achieving the effects of improving C2 yield, methane single-pass conversion rate and alkene-alkane ratio.

[0067] In some instances, the solid solution catalyst is activated prior to participating in the coupling reaction, thereby enhancing its catalytic activity.

[0068] In some instances, the activation conditions for the solid solution catalyst include: a temperature of 500°C–800°C (e.g., 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, or any combination of the above values), a time of 0.5h–12h (e.g., 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, or any combination of the above values), and an atmosphere of one or more of pure hydrogen, diluted hydrogen, nitrogen, argon, and air. Diluted hydrogen refers to a mixture of hydrogen and argon, with a hydrogen volume content of 5%–10%.

[0069] In some instances, the coupling reaction temperature is 600°C-680°C (e.g., 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, or within any two of these values). Under the catalytic action of the solid solution catalyst of the present invention, the reaction temperature of the coupling reaction can be controlled below 700°C, thereby reducing the risk of catalyst sintering and structural instability.

[0070] In some instances, the space velocity of the coupling reaction is 3000 mL·g. cat -1 ·h -1 -100000 mL·g cat -1 ·h -1 (For example, 3000 mL·g) cat -1 ·h -1 5000mL·g cat -1 ·h -1 8000mL·g cat -1 ·h -1 10000mL·g cat -1 ·h -1 20000mL·g cat -1 ·h -1 30000mL·g cat -1 ·h -1 40000mL·g cat -1 ·h -1 50000mL·g cat -1 ·h -1 60000mL·g cat-1 ·h -1 70000mL·g cat -1 ·h -1 80000mL·g cat -1 ·h -1 90000mL·g cat -1 ·h -1 100000mL·g cat -1 ·h -1 ).

[0071] In some instances, the molar flow rate ratio of nitrous oxide to methane is (0.1-10):1 (e.g., 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or within any range of two of the above values).

[0072] The fourth aspect of this invention provides a method for regulating the catalytic coupling reaction of nitrous oxide reduction and methane oxidation using a solid solution catalyst. The solid solution catalyst is the solid solution catalyst described in the first aspect of this invention and / or a solid solution catalyst prepared by the preparation method described in the second aspect of this invention. The nitrous oxide reduction and methane oxidation coupling reaction is the coupling reaction described in the third aspect of this invention. The method for regulating the catalytic coupling reaction of nitrous oxide reduction and methane oxidation using a solid solution catalyst satisfies the following relationship: 3 ≤ B / (A×S) ≤ 200 (e.g., 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 or within any two of the above values), where B is the molar flow rate of the nitrous oxide in mol / h; A is the molar flow rate of Gd in the solid solution catalyst. 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage; S is the total molar amount of the solid solution catalyst used, in mol.

[0073] By controlling the relationship: 3≤B / (A×S)≤200, the matching degree between the rate of N2O release of oxide species and the activation rate of methane can be regulated, thereby realizing the regulation of the synergistic methane oxidation coupling reaction of nitrous oxide reduction by solid solution catalyst, and improving C2 yield, methane single-pass conversion and alkene-alkane ratio.

[0074] In some instances, B is 0.0012-0.12 (e.g., 0.0012, 0.002, 0.003, 0.005, 0.006, 0.007, 0.008, 0.1, 0.11, 0.12, or any two of these values).

[0075] In some instances, S is 0.000056-0.0028 (e.g., 0.000056, 0.00006, 0.00008, 0.0001, 0.0003, 0.0005, 0.0008, 0.001, 0.0013, 0.0015, 0.0018, 0.002, 0.0023, 0.0025, 0.0028, or within any two of the above values).

[0076] The fifth aspect of the present invention provides a reaction system for a nitrous oxide reduction-coordinated methane oxidative coupling reaction, the reaction system comprising a feed gas supply unit, a reaction unit, a temperature control unit, and a product analysis unit.

[0077] The various units are interconnected via pipelines to form a continuous flow system. The feed gas supply unit introduces N₂O and CH₄ separately, and independently adjusts their respective feed flow rates to meet the feed ratio requirements under different reaction conditions. The reaction unit employs a fixed-bed reactor structure, with a solid solution catalyst bed filled with a precipitated, crushed, and sieved material, ensuring sufficient contact between the reactant gases and the catalyst as they pass through the bed. This solid solution catalyst bed includes the solid solution catalyst described in the first aspect of this invention and / or a solid solution catalyst prepared by the preparation method described in the second aspect of this invention. A temperature control unit heats the fixed-bed reactor in the reaction unit and monitors the reaction temperature in real time, thereby maintaining stable operation of the fixed-bed reactor within a set temperature range. The product analysis unit performs component analysis on the reaction tail gas, using gas chromatography (GC), specifically gas chromatography analysis technology, for the quantitative detection of methane, ethylene, ethane, carbon dioxide, and unreacted nitrous oxide in the reaction products.

[0078] During the reaction system operation, N₂O is first selectively adsorbed and activated on the surface of the solid solution catalyst, breaking down to generate reactive surface oxygen species. These surface oxygen species, under the regulation of the lattice environment of the solid solution catalyst, participate in the initial activation process of CH₄ at a limited rate, promoting the formation of methyl intermediates (e.g., methyl radicals), and further generating two-carbon products such as ethane and ethylene through coupling reactions. Since the crystal structure of the solid solution catalyst regulates the rate of N₂O oxygen species release and the migration behavior of these oxygen species, the solid solution catalyst can effectively reduce the probability of deep oxidation reactions between reactive oxygen and CH₄ and two-carbon intermediates, thereby achieving high C₂ selectivity and a high alkene-to-alkane ratio at lower reaction temperatures.

[0079] In this invention, the olefin-to-alkane ratio refers to the molar ratio of ethylene to ethane in the products ethane and ethylene generated by the nitrous oxide reduction-coupling reaction with methane oxidative coupling.

[0080] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0081] The following examples illustrate the solid solution catalyst of this application and its application.

[0082] Example 1 (1) Preparation of solid solution catalysts Weigh 12.5 mmol Gd(NO3)3·6H2O and 7.5 mmol Sm(NO3)3·6H2O to prepare a 100 mL precursor aqueous solution and place it in a 500 mL beaker. Add ammonia water dropwise to the precursor aqueous solution at 30℃ and stir at 600 r / min. When the pH of the solution reaches 10, obtain the precipitate mother liquor, age it at 30℃ for 1 h, wash it three times with deionized water, filter it, dry the resulting filter cake at 80℃, and calcine it in air at 800℃ for 3 h to obtain catalyst powder, denoted as 38% SmGdO. x Tablet, crush, and screen with a mesh size of 40-60 for evaluation.

[0083] (2) Application of solid solution catalysts in nitrous oxide reduction synergistic methane oxidative coupling reaction 0.2 g of pre-pressed solid solution catalyst and 0.8 g of quartz sand (40-60 mesh) were weighed and loaded into the reaction tube of a fixed-bed continuous flow reactor with an inner diameter of 6 mm. The catalyst was fixed in two layers with quartz wool. The reaction was carried out at atmospheric pressure (0.1 MPa). The reaction temperature was measured by a thermocouple placed in the middle of the reaction tube and controlled by a programmed temperature controller. The gas flow rate was controlled by a mass flow meter. The reactor was pretreated in pure Ar at 650 °C for 2 h at atmospheric pressure and a flow rate of 30 mL / min. Then, a feed gas with a composition of n(CH4):n(N2O):n(He) = 30%:15%:55% was introduced. The reaction was carried out at atmospheric pressure, 650 °C, and GHSV = 30000 mL·gcat. -1 ·h -1 The test was conducted under the following conditions. Where A = 0.38, B = (30 mL / min × 10⁻⁶). -3 (×15%×60min / h) / 22.4L / mol=0.012mol / h, S=0.2 / 357.26=0.00056mol. Considering that the relative atomic weights of elements Sm and Gd are similar, the molar molecular weight of the solid solution catalyst in all examples and comparative examples is calculated as 357.26 g / mol, so B / (A×S)=56.4.

[0084] Example 2 The procedure was carried out in accordance with Example 1, except that the metal salts were 16 mmol Gd(NO3)3·6H2O and 4 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 20%SmGdO. x .

[0085] Example 3 The procedure was carried out in accordance with Example 1, except that the metal salts were 13.3 mmol Gd(NO3)3·6H2O and 6.7 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 33%SmGdO. x .

[0086] Example 4 The procedure was carried out in accordance with Example 1, except that the metal salts were 11.2 mmol Gd(NO3)3·6H2O and 8.8 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 44%SmGdO. x .

[0087] Example 5 The procedure was carried out in accordance with Example 1, except that the metal salts were 10.4 mmol Gd(NO3)3·6H2O and 9.6 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 48%SmGdO. x .

[0088] Example 6 The procedure was carried out in accordance with Example 1, except that the metal salts were 19.9 mmol Gd(NO3)3·6H2O and 0.1 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 0.5% SmGdO. x .

[0089] Example 7 The procedure was carried out in accordance with Example 1, except that the metal salts were 18 mmol Gd(NO3)3·6H2O and 2 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 10%SmGdO. x .

[0090] Example 8 The same procedure was followed as in Example 5, except that the total amount of solid solution catalyst and quartz sand was kept to be 1g, and the S was adjusted to 0.0028 by adjusting the amount of quartz sand.

[0091] Example 9 The same procedure was followed as in Example 5, except that the total amount of solid solution catalyst and quartz sand was kept to be 1g, and S was adjusted to 0.00014 by adjusting the amount of quartz sand.

[0092] Comparative Example 1 The procedure was carried out in accordance with Example 1, except that the metal salts were 10 mmol Gd(NO3)3·6H2O and 10 mmol Sm(NO3)3·6H2O, and the resulting solid solution catalyst was designated as 50%SmGdO. x .

[0093] Comparative Example 2 The procedure was carried out in accordance with Example 1, except that the metal salt was 20 mmol Gd(NO3)3·6H2O, and the resulting solid catalyst was designated as Gd2O3. The application of the solid catalyst Gd2O3 in the nitrous oxide reduction-coupling reaction with synergistic methane oxidation was performed in accordance with the application of the solid solution catalyst in the nitrous oxide reduction-coupling reaction with synergistic methane oxidation in Example 1.

[0094] Comparative Example 3 The procedure was carried out in accordance with Example 1, except that the metal salt was 20 mmol Sm(NO3)3·6H2O, and the resulting solid catalyst was designated as Sm2O3. The application of the solid catalyst Sm2O3 in the nitrous oxide reduction-assisted methane oxidative coupling reaction was performed in accordance with the application of the solid solution catalyst in the nitrous oxide reduction-assisted methane oxidative coupling reaction in Example 1.

[0095] Comparative Example 4 44% SmGdO prepared by mechanical mixing method x-M, M=Mixed. 11.2 mmol of Gd(NO3)3·6H2O was precipitated with ammonia until pH 10. The resulting precipitate was filtered, washed, dried, and calcined in air at 800°C for 3 h to obtain Gd2O3. 8.8 mmol of Sm(NO3)3·6H2O was precipitated with ammonia until pH 10. The resulting precipitate was filtered, washed, dried, and calcined in air at 800°C for 3 h to obtain Sm2O3. The catalyst obtained by mechanically mixing the above Gd2O3 and Sm2O3 was 44% SmGdO. x -M. Catalyst 44% SmGdO x The application of -M in the nitrous oxide reduction-coupling reaction with methane oxidation is carried out in accordance with the application of solid solution catalyst in the nitrous oxide reduction-coupling reaction with methane oxidation in Example 1.

[0096] Comparative Example 5 44% SmGdO prepared by impregnation method x -S, S=Supported. 11.2 mmol of Gd(NO3)36H2O was precipitated with ammonia until pH 10. The precipitate was filtered, washed, dried, and calcined in air at 800℃ for 3 h to obtain Gd2O3. 8.8 mmol of Sm(NO3)36H2O was dissolved in 44 mL of deionized water. The above Gd2O3 was added to a samarium nitrate aqueous solution, sonicated for 10 min, stirred and evaporated to dryness in an oil bath at 110℃, and calcined in air at 800℃ for 3 h. The resulting catalyst was 44% SmGdO3. x -S (Understandably, 44% SmGdO) x -S is Sm2O3 supported on the surface of Gd2O3). Catalyst 44% SmGdO x The application of -S in the nitrous oxide reduction-coupling reaction with methane oxidation is carried out in accordance with the application of solid solution catalyst in the nitrous oxide reduction-coupling reaction with methane oxidation in Example 1.

[0097] The results are recorded in Tables 1-1 and 1-2.

[0098] Table 1-1 " / " indicates that it does not exist.

[0099] Table 1-2 Wherein, CH4 conversion rate (%) = (1 - (methane discharge rate after reaction / methane inflow rate)) × 100%; C2 selectivity (%) = ((2 × 100% molar flow rate of ethylene + 2 × molar flow rate of ethane) / (methane inlet flow rate - methane outlet flow rate after reaction)) × 100%; C2 yield (%) = (CH4 conversion × C2 selectivity) × 100%.

[0100] As can be seen from Tables 1-1 and 1-2, by comparing the comparative examples and the embodiments, the solid solution catalyst prepared in the embodiments, when applied to the nitrous oxide reduction-coordinated methane oxidative coupling reaction, significantly improves the C2 selectivity and the C2 yield, indicating that the introduction of Sm into Gd2O3... 3+ , making Sm 3+ Equivalent replacement of part of Gd 3+ Simultaneously controlling the amount of Gd in the solid solution catalyst 3+ and Sm 3+ The total sum of moles is used as the benchmark Sm 3+ The molar ratio improves the problem of low matching between oxide release rate and methane activation rate in N2O-OCM reaction.

[0101] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A solid solution catalyst, characterized in that, The solid solution catalyst comprises a Gd₂O₃ lattice matrix and Sm₂ located in the Gd₂O₃ lattice matrix. 3+ The solid solution catalyst includes Gd 3+ and Sm 3+ Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage A is 0.5% ≤ A < 50%.

2. The solid solution catalyst according to claim 1, wherein, With the Gd in the solid solution catalyst 3+ and Sm 3+ Based on the total moles, Sm 3+ The molar percentage A is 20% ≤ A ≤ 45%; And / or, in the solid solution catalyst, Gd 3+ and Sm 3+ The sum of total moles and O 2- The molar ratio is (1.9-2.1):(2.9-3.1).

3. The solid solution catalyst according to claim 1, wherein, In the XRD pattern of the solid solution catalyst, the peak value of the 222 crystal plane diffraction peak has a 2θ of 28.42°-28.69°. And / or, the solid solution catalyst does not include an independently distributed Sm2O3 phase.

4. The solid solution catalyst according to any one of claims 1-3, wherein, The solid solution catalyst further includes a first metal, which is selected from one or more of alkali metals, alkaline earth metals, transition metals, rare earth metals, and noble metals.

5. The solid solution catalyst according to claim 4, wherein, The alkali metal is selected from one or more of Na, K, and Cs; And / or, the alkaline earth metal is selected from one or more of Mg, Ca, Sr and Ba; And / or, the transition metal is selected from one or more of Fe, Co, Ni, Cu and Mn; And / or, the rare earth metal is selected from one or more of La, Ce, Pr, Tb and Y; And / or, the noble metal is selected from one or more of Ir, Pt, Pd and Ru; And / or, the first element exists in the solid solution catalyst in a doping or mechanical mixing manner; And / or, based on the total weight of the solid solution catalyst, the weight percentage of the first metal is 0%-2%.

6. A method for preparing a solid solution catalyst, characterized in that, The solid solution catalyst prepared by the preparation method is the solid solution catalyst according to any one of claims 1-5, wherein the preparation method includes: S1: Mix the soluble metal salt of Sm, the soluble metal salt of Gd, and water to form the first solution; S2: The first solution and the precipitant undergo a first contact, and a precipitate is obtained through solid-liquid separation; S3: The precipitate is roasted.

7. The preparation method according to claim 6, wherein, The soluble metal salt of Sm is selected from one or more of samarium nitrate, samarium acetate, samarium halide, and samarium sulfate; And / or, the soluble metal salt of said Gd is selected from one or more of gadolinium nitrate, gadolinium acetate, gadolinium halide and gadolinium sulfate; And / or, the precipitant is selected from one or more of ammonia, urea, ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide; And / or, the conditions for the first contact include: a temperature of 20°C-90°C and a pH of 8-13; And / or, the calcination conditions include: a temperature of 600℃-1000℃, a time of 2h-24h, and a calcination atmosphere selected from one or more of air, oxygen, and nitrogen; And / or, in the first solution, the total concentration of metal ions is 0.01 mol / L to 1 mol / L; And / or, prior to step S3, the precipitate is further aged, washed, and dried.

8. The preparation method according to claim 7, wherein, The aging conditions include: a temperature of 50℃-90℃ and a time of 0.5h-6h; And / or, the washing conditions include: the washing solution is selected from one or more of deionized water, ethanol, and methanol, and washing is performed until the pH of the supernatant is 7-8; And / or, the drying conditions include: a temperature of 60°C-140°C and a time of 8h-24h.

9. A nitrous oxide reduction-coordinated methane oxidative coupling reaction, characterized in that, The methane oxidative coupling reaction is a chemical reaction in which nitrous oxide provides an oxygen source and methane is oxidized to produce ethane and / or ethylene. The catalyst for the methane oxidative coupling reaction is the solid solution catalyst of any one of claims 1-5 and / or the solid solution catalyst prepared by the preparation method of any one of claims 6-8.

10. The coupling reaction according to claim 9, wherein, The activation conditions for the solid solution catalyst include: a temperature of 500℃-800℃, a time of 0.5h-12h, and an atmosphere of one or more of pure hydrogen, diluted hydrogen, nitrogen, argon, and air. And / or, the reaction temperature of the coupling reaction is 620℃-680℃; And / or, the molar flow rate ratio of the nitrous oxide to the methane is (0.1-10):

1.

11. A method for regulating the catalytic coupling reaction of nitrous oxide reduction and methane oxidation using a solid solution catalyst, characterized in that, The solid solution catalyst is the solid solution catalyst according to any one of claims 1-5 and / or the solid solution catalyst prepared by the preparation method according to any one of claims 6-8. The nitrous oxide reduction-coupling reaction with methane oxidation is the coupling reaction according to claim 9 or 10. The method for regulating the solid solution catalyst to catalyze the nitrous oxide reduction-coupling reaction with methane oxidation satisfies the following relationship: 3≤B / (A×S)≤200, where B is the molar flow rate of the nitrous oxide in mol / h; A is the molar flow rate of Gd in the solid solution catalyst. 3+ and Sm 3+ Based on the total sum of moles, Sm 3+ The molar percentage; S is the total molar amount of the solid solution catalyst used, in mol.

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