Preparation method and application of a sponge-like porous lanthanum oxide-based catalyst

Abstract

This invention discloses a method for preparing a sponge-like porous lanthanum oxide-based catalyst and its application, relating to the field of chemical catalyst technology. The preparation method is a solvent combustion method, specifically including adding a lanthanum precursor to water to obtain a solution; adding fuel and an oxidant to the solution, heating and stirring in a water bath until the water evaporates to form a viscous liquid; calcining the viscous liquid at 300-500°C for 1-5 hours, followed by calcination at 800°C for 4-12 hours to obtain a sponge-like porous La2O3 catalyst. This catalyst not only possesses a rich pore structure and a large specific surface area, but also efficiently catalyzes the oxidative coupling reaction of methane at an ultra-low temperature of 400°C to produce ethylene, ethane, and other C2O3. 2+ Hydrocarbons; well-developed pores facilitate the diffusion of reactants on the catalyst and significantly inhibit deep oxidation processes, thereby affecting C 2+ Hydrocarbons achieve high selectivity.

Description

Technical Field

[0001] This invention relates to the field of chemical catalyst technology, specifically to a method for preparing a sponge-like porous lanthanum oxide catalyst and its application. Background Technology

[0002] Ethylene is a basic chemical raw material for many chemicals, such as synthetic fibers, synthetic plastics, and synthetic rubber. Methane-to-ethylene conversion transforms low-value CH4 into high-value ethylene, achieving the high-value utilization of methane. Among various technical routes, oxidative coupling of methane (OCM) to ethylene has received widespread attention as an effective means of direct methane utilization. In recent years, the discovery of shale gas and coalbed methane has provided even more abundant methane feedstocks, further promoting the development of OCM technology.

[0003] In OCM technology, the key lies in developing highly efficient OCM reaction catalysts. Among existing catalysts, Na / W / Mn / SiO2 catalysts exhibit the best OCM reaction performance, achieving a C2 yield of 25%-30% at 800℃. The high reaction temperature limits the industrial application of Na-W-Mn / SiO2 catalysts. La-based catalysts show good low-temperature activity, but their C2 yield is relatively low. Therefore, an ideal methane oxidative coupling catalyst should balance low temperature and high reactivity.

[0004] Researchers have modified existing catalysts in various ways to obtain high activity at low temperatures. Specifically, regarding Na-W-Mn / SiO2 catalysts, Lu Yong et al. constructed a Mn2O3-Na2WO4-MnTiO3 / SiO2 catalyst using three active components—Mn2O3, Na2WO4, and MnTiO3—with a SiO2 support. This catalyst achieved a 27% methane conversion and a 76% C2-C3 hydrocarbon selectivity at temperatures between 620 and 700 °C (CN106964341B). Song et al. modified Na-W-Mn / SiO2 catalysts with Ce, and the 3Ce-MnOx / NaWSi composite catalyst achieved a CH4 conversion of 38.4% and a C2 yield of 15.6% at 700 °C (Ce-Driven Ce-MnOx / Na2WO4 / SiO2Composite Catalysts for Low Temperature Oxidative Coupling of Methane. ACS Catal. 2024, 14, 5116−5131). Although the temperature was lowered, the reaction temperature still exceeded 600 °C.

[0005] Lanthanum-based catalysts can perform OCM reactions at lower reaction temperatures. Wu Jiehua et al. synthesized various morphologies of lanthanum oxycarbonate and lanthanum hydroxide catalysts for OCM reactions (CN113797949B, CN115463651B, CN115382562A, CN115463678A), among which the nanorod-shaped La2O2CO3 catalyst can achieve a carbon content of approximately 12% at a minimum of 437℃. 2+ Yield. Metal modification allows for further enhancement of the catalyst's C content at 500-650℃. 2+ The yield was increased to approximately 15%-18% (CN120303059B, CN117816213B, CN115382562A). Feng Ru et al. synthesized a nano-flower-like La2O2CO3 catalyst that achieved a 12% C content at 375℃. 2+ Yield (CN109663587A). Emel Engintepe et al. obtained a La2O2CO3 catalyst with 12.3% C content at temperatures up to 350°C using ammonia as a precipitant. 2+ Yield (Engintepe, E., Özdemir, H., Öksüzömer, MAF et al. Hydrothermal Synthesis of La2O2CO3 and La2O3 Catalysts: Influence of Alkaline Solution on Low-Temperature OCM Performance. Top Catal (2026). https: / / doi.org / 10.1007 / s11244-026-02288-z). This demonstrates that modifying the preparation method of lanthanum-based catalysts is an effective means to achieve low-temperature catalysis. Although the above catalysts have achieved low-temperature activation of methane, the catalyst preparation methods are mostly hydrothermal, with complex processes, and the OCM reaction performance remains low. Therefore, to develop truly low-temperature, high-activity OCM reaction catalysts, it is still necessary to focus on lanthanum-based catalysts and optimize catalyst morphology and structure to achieve ideal OCM reaction conditions. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and proposes a method for preparing a sponge-like porous lanthanum oxide catalyst and its application. This invention is achieved through the following technical solution: A method for preparing a sponge-like porous lanthanum oxide-based catalyst includes the following steps: S1. Add the lanthanum precursor to water to obtain a solution; S2. Add fuel and oxidant to the solution, heat and stir in a water bath until the water evaporates to form a viscous liquid; S3. The viscous liquid is calcined at 300-500℃ for 1-5 hours, and then calcined at 800℃ for 4-12 hours to obtain a sponge-like porous La2O3 catalyst.

[0007] Preferably, the molar ratio of fuel: oxidant: total metal: water is 1~2.5:1~7.5:1:100~200.

[0008] Preferably, the lanthanum precursor is lanthanum nitrate and / or lanthanum acetate.

[0009] Preferably, the fuel is one or any combination of urea, hexamethylenetetramine, citric acid, glycine, glutamic acid, and glucose.

[0010] Preferably, the oxidant is nitric acid and / or ammonium nitrate.

[0011] Preferably, the water bath heating temperature is 60-100℃.

[0012] Preferably, the solution in step S1 further contains an oxide precursor.

[0013] Preferably, the oxide precursor is one or any combination of cerium nitrate, strontium nitrate, magnesium nitrate, and barium acetate.

[0014] Preferably, the viscous liquid is calcined at 450°C for 2 hours, and then calcined at 800°C for 8 hours to obtain a sponge-like porous La2O3 catalyst.

[0015] Application of the catalyst prepared by the method described above in the oxidative coupling of methane to ethylene.

[0016] The beneficial effects of this invention compared to the prior art are as follows: This invention provides a sponge-like porous lanthanum oxide-based catalyst prepared by combustion. This catalyst not only possesses abundant pore structure and a large specific surface area, but also efficiently catalyzes the oxidative coupling reaction of methane at an ultra-low temperature of 400°C, producing ethylene, ethane, and other C4 compounds. 2+ Hydrocarbons. Well-developed pores facilitate the diffusion of reactants across the catalyst and significantly inhibit deep oxidation processes, thereby reducing the impact on C. 2+ The catalyst achieves high selectivity for hydrocarbons (up to 68% under optimized conditions). Furthermore, it fully utilizes the active components, operates over a wide temperature range, exhibits excellent stability, and is economically viable, demonstrating promising industrial application prospects in the oxidative coupling of methane to C2 hydrocarbons. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope image of the La2O3 catalyst prepared in Example 1; Figure 2 This is a scanning electron microscope image of the Sr-La2O3 catalyst prepared in Example 4; Figure 3 This is a scanning electron microscope image of the Mg-Ce-La2O3 catalyst prepared in Example 9; Figure 4 This is a scanning electron microscope image of the rod-shaped La2O3 catalyst prepared in Comparative Example 2. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto. Example 1

[0019] A method for preparing a sponge-like porous coupled La2O3 catalyst, specifically comprising the following steps: S1. Weigh 10 mmol of lanthanum nitrate (4.33 g) and dissolve it in about 50 mL of deionized water; add 30 mmol of glycine (fuel) and 15 mmol of nitric acid (oxidant) to obtain a mixture with a molar ratio of fuel:oxidant:total metal = 3:1.5:1.

[0020] S2. Heat and stir the mixture in a 100°C water bath until the water is completely evaporated to form a viscous liquid. Calcinate the resulting material at 450°C for 2 hours, then at 800°C for 6 hours to obtain a sponge-like porous La2O3 catalyst.

[0021] S3. The catalyst is compressed into tablets and crushed into 20-40 mesh particles, then loaded into a fixed-bed quartz tube reactor. The methane oxidative coupling reaction is carried out under atmospheric pressure, specifically with CH4 / O2 = 3 and space velocity = 10000 h⁻¹. -1 The reaction temperatures were 450℃ and 500℃. The reaction results are shown in Table 1. Example 2

[0022] A method for preparing a sponge-like porous coupled Ce-La2O3 catalyst, specifically comprising the following steps: S1. Weigh 8 mmol lanthanum nitrate (3.46 g) and 2 mmol cerium nitrate (0.868 g), dissolve them in about 50 mL of deionized water, add 30 mmol glycine (fuel) and 50 mmol ammonium nitrate (oxidant), with a fuel:oxidant:total metal (10 mmol) molar ratio of 3:5:1.

[0023] S2. The mixture obtained above is heated and stirred in a water bath at 100°C until the water is completely evaporated. The resulting product is calcined at 450°C for 2 hours and then calcined at 800°C for 10 hours to obtain a sponge-like porous Ce-La2O3 catalyst.

[0024] S3. The catalyst is compressed into tablets and crushed to 20-40 mesh. Reaction conditions: CH4 / O2 = 3, space velocity = 20000 h⁻¹ -1 Temperatures were set at 400 and 450℃. The results are shown in Table 1. Example 3

[0025] The method for preparing pure sponge-like porous La2O3 catalyst specifically includes the following steps: S1. Dissolve 15 mmol of lanthanum acetate (approximately 5.28 g) in approximately 50 mL of deionized water, and add fuel and oxidant. The fuel is an equimolar mixture of urea and glucose (30 mmol each, totaling 60 mmol), and the oxidant is 112.5 mmol of ammonium nitrate (9.00 g). The molar ratio of fuel:oxidant:total metal is 60:112.5:15 = 4:7.5:1.

[0026] S2. After evaporating the water in the above mixture by means of a 100°C water bath, calcine at 500°C for 1 hour, and then at 800°C for 12 hours to obtain a sponge-like porous La2O3 catalyst.

[0027] S3. After the catalyst was tableted and crushed to 20-40 mesh, the methane oxidative coupling reaction was evaluated in a fixed-bed quartz tube reactor under the conditions of atmospheric pressure, CH4 / O2=4, and space velocity=40000 h⁻¹. -1 The reaction temperatures are 500℃ and 600℃, as shown in Table 1. Example 4

[0028] The preparation of Sr-modified sponge-like porous La2O3 catalyst (La:Sr=20:1) specifically includes the following steps: S1. Weigh 10 mmol lanthanum nitrate (4.33 g) and 0.5 mmol strontium nitrate (0.106 g), and dissolve them in about 50 mL of deionized water; add 12 mmol glucose (fuel) and 30 mmol nitric acid (oxidant, 65 wt%, about 1.89 g, take 2.9 mL), the molar ratio of fuel:oxidant:total metal is 12:30:10.5≈1.14:2.86:1.

[0029] S2. After evaporating the water in the above mixture by means of a 100°C water bath, calcine at 350°C for 4 hours, and then calcine at 800°C for 5 hours to obtain a sponge-like porous Sr-La2O3 catalyst.

[0030] S3. After the catalyst was compressed into tablets and crushed to 20-40 mesh, the methane oxidative coupling reaction was evaluated in a fixed-bed quartz tube reactor under the following conditions: atmospheric pressure, CH4 / O2 = 3, and space velocity = 20000 h⁻¹. -1 The reaction temperatures were 500℃ and 600℃, and the results are shown in Table 1. Example 5

[0031] The preparation of Mg-modified sponge-like porous La2O3 catalyst (La:Mg=8:1) specifically involves the following steps: S1. Weigh 10 mmol lanthanum nitrate (4.33 g) and 1.25 mmol magnesium nitrate (0.320 g), and dissolve them in about 50 mL of deionized water; add 20 mmol citric acid (fuel) and 50 mmol nitric acid (oxidant, 65 wt%, about 3.15 g, take 4.8 mL), the molar ratio of fuel:oxidant:total metal = 20:50:11.25≈1.78:4.44:1.

[0032] S2. After evaporating the water in the above mixture by means of a 100℃ water bath, calcine at 450℃ for 2 hours, and then at 800℃ for 8 hours to obtain a sponge-like porous Mg-La2O3 catalyst.

[0033] S3. The obtained catalyst is compressed into tablets and crushed into 20-40 mesh, then loaded into a fixed-bed quartz tube reactor. Methane oxidative coupling reaction is carried out under atmospheric pressure, specifically with CH4 / O2 = 4 and space velocity = 160,000 h⁻¹. -1 The reaction temperatures were 500℃ and 600℃, and the results are shown in Table 1. Example 6

[0034] The preparation of Ba-modified sponge-like porous La2O3 catalyst (La:Ba=50:1) specifically involves the following steps: S1. Weigh 10 mmol lanthanum acetate (approximately 3.52 g) and 0.2 mmol barium acetate (0.051 g), dissolve them in approximately 50 mL of deionized water, add 25 mmol hexamethyleneamine (fuel) and 70 mmol ammonium nitrate (oxidant), the molar ratio of fuel:oxidant:total metal = 25:70:10.2≈2.45:6.86:1.

[0035] S2. After evaporating the water in the above mixture by means of a 100°C water bath, the mixture is first calcined at 450°C for 2.5 hours, and then calcined at 800°C for 12 hours to obtain a sponge-like porous Ba-La2O3 catalyst.

[0036] S3. The catalyst is compressed into tablets and crushed into 20-40 mesh. The methane oxidative coupling reaction is then carried out in a fixed-bed quartz tube reactor under atmospheric pressure, specifically with CH4 / O2 = 2 and space velocity = 10000 h⁻¹. -1 The reaction temperatures are 500℃ and 600℃, as shown in Table 1. Example 7

[0037] The preparation of a Sr and Ce composite modified sponge-like porous La2O3 catalyst involves the following steps: S1. Weigh 16 mmol lanthanum nitrate (6.50 g), 3 mmol cerium nitrate (1.30 g), and 1 mmol strontium nitrate (0.260 g), dissolve them in about 50 mL of deionized water, and add fuel and oxidant. The fuel is an equimolar mixture of glycine and citric acid (15 mmol each, 30 mmol in total), and the oxidant is 80 mmol ammonium nitrate (6.5 g). The molar ratio of fuel:oxidant:total metal is approximately 30:80:20:3:8:2.

[0038] S2. After evaporating the water in the above mixture by means of a 100℃ water bath, calcine at 380℃ for 5 hours, and then calcine at 800℃ for 9 hours to obtain a sponge-like porous Sr-Ce-La2O3 catalyst.

[0039] S3. The catalyst is compressed into tablets and crushed into 20-40 mesh. Methane oxidative coupling reaction is then carried out in a fixed-bed quartz tube reactor under atmospheric pressure, specifically with CH4 / O2 = 8 and space velocity = 20000 h⁻¹. -1 The reaction temperatures are 450℃ and 500℃, as shown in Table 1. Example 8

[0040] The preparation of a Ba and Ce composite modified high La / M ratio sponge-like porous La2O3 catalyst involves the following steps: S1. Using 15 mmol lanthanum acetate (approximately 5.28 g), 0.05 mmol barium acetate (0.0128 g), and 0.1 mmol cerium nitrate (0.0434 g) as metal sources, dissolve them in approximately 50 mL of deionized water; add 15 mmol glycine (fuel) and 22.5 mmol nitric acid (oxidant, 65 wt%, approximately 1.42 g, take 2.2 mL), the molar ratio of fuel:oxidant:total metal is approximately 15:22.5:15.15:0.99:1.49:1.

[0041] S2. After evaporating the water in the above mixture by means of a 100°C water bath, it is first calcined at 300°C for 5 hours, and then calcined at 800°C for 4 hours to obtain a sponge-like porous Ba-Ce-La2O3 catalyst.

[0042] S3. Compress the catalyst into tablets and crush them to 20-40 mesh, then load them into a fixed-bed quartz tube reactor. Conduct the methane oxidative coupling reaction under atmospheric pressure, specifically with CH4 / O2 = 3 and space velocity = 20000 h⁻¹. -1 The reaction temperatures were 550℃ and 650℃, and the results are shown in Table 1. Example 9

[0043] The preparation of a Mg and Ce composite modified sponge-like porous La2O3 catalyst involves the following steps: S1. Weigh 7 mmol lanthanum nitrate (3.03 g), 2 mmol cerium nitrate (0.868 g) and 1 mmol magnesium nitrate (0.256 g), and dissolve them in about 50 mL of deionized water; add 60 mmol glycine (fuel) and 50 mmol nitric acid (65 wt%, about 3.15 g, take 4.8 mL) as oxidant, so that the molar ratio of fuel:oxidant:total metal (10 mmol) is 6:5:1.

[0044] S2. After evaporating the water in the above mixture through a 100°C water bath to form a viscous liquid, it is then calcined at 450°C for 2 hours and then at 800°C for 8 hours to obtain a sponge-like porous Mg-Ce-La2O3 catalyst.

[0045] S3. Compress the catalyst into tablets and crush them into 20-40 mesh, then load them into a fixed-bed quartz tube reactor. Conduct the methane oxidative coupling reaction under atmospheric pressure, specifically: CH4 / O2 = 4, space velocity = 40000 h⁻¹. -1 The reaction temperatures were 400℃ and 500℃. The reaction results are shown in Table 1. Example 10

[0046] The preparation of a Sr, Mg, and Ce composite modified sponge-like porous La2O3 catalyst specifically involves the following steps: S1. Weigh 6 mmol of lanthanum nitrate (3.03 g), 2 mmol of cerium nitrate (0.868 g), 1 mmol of strontium nitrate (0.260 g), and 1 mmol of magnesium nitrate (0.256 g), and dissolve them in approximately 50 mL of deionized water. Add 60 mmol of glycine (fuel) and 50 mmol of nitric acid (oxidant, 65 wt%, approximately 3.15 g, take 4.8 mL) as oxidants, making the fuel:oxidant:total metal molar ratio 6:5:1.

[0047] S2. After evaporating the water in the above mixture through a 100°C water bath to form a viscous liquid, it is then calcined at 300°C for 2 hours and then at 800°C for 8 hours to obtain a sponge-like porous Sr-Mg-Ce-La2O3 catalyst.

[0048] S3. The catalyst powder after the reaction was directly loaded into a fixed-bed quartz tube reactor for evaluation. The methane oxidative coupling reaction was carried out under atmospheric pressure, with the specific conditions being: CH4 / O2 = 4, space velocity = 40000 h⁻¹. -1 The reaction temperatures were 400℃ and 500℃. The reaction results are shown in Table 1.

[0049] Comparative Example 1 Preparation of 5wt% Na2WO4-2wt% MnO x / SiO2 catalyst, specifically the following steps: S1. Add 5 g of SiO2 support to 15 mL of deionized water and pretreat at 105 °C with stirring for 1 hour; then add 0.30 g of Na2WO4 and 0.45 g of 50% Mn(NO3)2 solution in sequence (the amounts of both are calculated based on Na2WO4 accounting for 5 wt% and MnOx accounting for 2 wt% in the final catalyst), and continue stirring to ensure that the active components are fully mixed with the support to form a uniform slurry; S2. The obtained slurry is dried at 110℃ for 12 hours, then ground and transferred to a muffle furnace. It is calcined at 800℃ for 4 hours at a heating rate of 5℃ / min. After natural cooling, 5wt%Na2WO4-2wt%MnO is obtained. x / SiO2 catalyst.

[0050] S3. The catalyst is compressed into tablets and crushed into 20-40 mesh, then loaded into a fixed-bed quartz tube reactor. The methane oxidative coupling reaction is carried out under atmospheric pressure, specifically: CH4 / O2 = 3, space velocity = 10000 h⁻¹. -1 The reaction temperatures were 700℃ and 800℃. The reaction results are shown in Table 1.

[0051] Comparative Example 2 The preparation of nanorod-shaped lanthanum oxide catalysts specifically involves the following steps: S1. Dissolve 1g of lanthanum nitrate in 50 mL of deionized water and stir until dissolved. Then adjust the pH to 11.5 with 10 wt% NaOH solution and continue stirring for 30 minutes. Transfer the white slurry to a 100 mL polytetrafluoroethylene-lined reactor and hydrothermally react at 160℃ for 12 hours, then allow it to cool naturally to room temperature.

[0052] S2, after being washed 6 times with alternating water and ethanol, dried at 80°C for 12 hours, calcined at 800°C for 4 hours, and naturally cooled, yielded nanorod-shaped La2O3 catalyst.

[0053] S3. The catalyst is compressed into tablets and crushed into 20-40 mesh, then loaded into a fixed-bed quartz tube reactor. The methane oxidative coupling reaction is carried out under atmospheric pressure, specifically: CH4 / O2 = 3, space velocity = 20000 h⁻¹. -1The reaction temperatures are 450℃ and 500℃.

[0054] ; The above experimental results show that this invention prepares a sponge-like porous La2O3 catalyst by combustion for the oxidative coupling reaction of methane. This catalyst is effective under normal pressure, 450–700°C, CH4 / O2 ratio of 8.0–2.0, and volume hourly space velocity of 10,000–100,000 h⁻¹. -1 Under the specified conditions, it exhibits excellent catalytic performance: CH4 conversion of 20.40%–34.59% and C2 hydrocarbon selectivity of 41.50%–68.30%. Under preferred conditions, the conversion can reach 34.59% and the selectivity is 68.30%. Compared with Comparative Example 1, the catalyst prepared in this invention has better low-temperature activity than the Na-W-Mn / SiO2 catalyst, indicating that lanthanum-based catalysts have advantages in low-temperature reactions. Among lanthanum-based catalysts, the nanorod-shaped La2O3 of Comparative Example 2 is a typical low-temperature catalyst, achieving 11.57% C2 conversion even at a low temperature of 450℃. 2+ Yield. Examples 2 and 9 of this invention exhibit superior low-temperature activity under even lower reaction conditions (400°C). The remaining examples show higher low-temperature reactivity at similar temperatures. Comparison of SEM images reveals that the sponge-like porous lanthanum oxide catalyst prepared in this invention has a larger specific surface area due to its abundant porous structure compared to the nanorod-packed La2O3 catalyst in Comparative Example 2. This facilitates contact between reactants and catalyst, as well as mass transfer between feed gas and product, thereby promoting the OCM reaction. All examples demonstrate that porous catalysts are beneficial for mass transfer and thus possess excellent low-temperature reaction characteristics, making them high-performance low-temperature methane oxidation coupling catalysts.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a sponge-like porous lanthanum oxide-based catalyst, characterized in that, Includes the following steps: S1. Add the lanthanum precursor to water to obtain a solution; S2. Add fuel and oxidant to the solution, heat and stir in a water bath until the water evaporates to form a viscous liquid; S3. The viscous liquid is calcined at 300-500℃ for 1-5 hours, and then calcined at 800℃ for 4-12 hours to obtain a sponge-like porous La2O3 catalyst.

2. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The molar ratio of fuel: oxidant: total metal: water is 1~2.5:1~7.5:1:100~200.

3. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The lanthanum precursor is lanthanum nitrate and / or lanthanum acetate.

4. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The fuel is one or any combination of urea, hexamethylenetetramine, citric acid, glycine, glutamic acid, and glucose.

5. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The oxidizing agent is nitric acid and / or ammonium nitrate.

6. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The water bath heating temperature is 60-100℃.

7. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The solution described in step S1 also contains an oxide precursor.

8. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 7, characterized in that, The oxide precursor is one or any combination of cerium nitrate, strontium nitrate, magnesium nitrate, and barium acetate.

9. The method for preparing a sponge-like porous lanthanum oxide-based catalyst according to claim 1, characterized in that, The viscous liquid was calcined at 450°C for 2 hours, and then calcined at 800°C for 8 hours to obtain a sponge-like porous La2O3 catalyst.

10. The application of the catalyst prepared by the preparation method according to any one of claims 1-9 in the oxidative coupling of methane to ethylene.

Images