Y0. 4Sr0. 6MnO3 perovskite porous loading material as well as synthesis method and application thereof

Abstract

The invention discloses a Y0. 4Sr0. 6MnO3 perovskite porous loading material as well as a synthesis method and application thereof, and belongs to the field of cracking CO2 fuel synthesis catalyst materials. The invention aims to solve the problems of low stability, low CO yield and low CO2 conversion rate of a catalytic material in a solar thermochemical fuel preparation process (two-step CO2 catalytic cracking). The method comprises the following steps: mixing EDTA (Ethylene Diamine Tetraacetic Acid) with an ammonia water solution, adding deionized water, heating in a water bath, and magnetically stirring; adding Y (NO3) 3.6 H2O, Mn (NO3) 2.4 H2O and Sr (NO3) 2 powder, and then adding citric acid monohydrate; adding ammonia water to adjust the pH value, and keeping heating and stirring; drying, grinding, calcining, then grinding, mixing with deionized water, dropwise attaching turbid liquid to the SiC porous framework, and purging; and drying. According to the preparation method, the Y0. 4Sr0. 6MnO3 powder material is attached to the SiC porous framework, so that the gas-solid reaction contact area of the powder material and CO2 is increased, and the oxidation-reduction reaction rate is increased; the heating rate of the material is accelerated, and the photo-thermal conversion efficiency and the overall efficiency are improved.

Description

Technical Field

[0001] The present invention belongs to the field of solar thermochemical photothermal synergistic cracking CO2 fuel synthesis catalyst materials, and specifically relates to a Y 0.4 Sr 0.6 MnO3 perovskite porous support material and its synthesis method and application. Background Art

[0002] Solar thermochemical CO2 catalytic cracking technology can convert solar energy into chemical energy to achieve effective utilization of renewable energy, and on the other hand, it can also reduce the CO2 content in the atmosphere, thereby alleviating the greenhouse effect. The two-step method is that the catalyst undergoes redox reaction at high temperature, and the reaction equation is as follows:

[0003]

[0004] The efficiency of the catalyst in the reaction process affects the overall efficiency of thermochemical fuel preparation to a certain extent. The present invention focuses on the ABO3 perovskite material, which is considered to have the most potential, and prepares a highly efficient Y 0.4 Sr 0.6 MnO3 catalyst, and proposed a suitable synthesis strategy. In addition, considering that powder materials are difficult to be directly applied to solar reactors, a synthesis method attached to a SiC porous skeleton is proposed to achieve the overall efficiency improvement of the solar thermochemical CO2 catalytic cracking system.

[0005] The catalyst materials currently used in solar thermochemical CO2 catalytic cracking have the following three common problems: (1) Due to the limitation of reaction kinetics, the CO yield is not high and the reaction rate is low. (2) The high temperature involved in solar thermochemical CO2 cracking technology can easily cause the material to sinter and reduce stability. (3) The gas-solid reaction efficiency is affected by the contact area, and how to increase the contact area between the material and CO2 is still a challenge.

[0006] Therefore, it is particularly important to develop a high-performance porous support material (with improved CO yield and sufficient stability). Summary of the invention

[0007] The present invention aims to solve the problems of low stability of catalytic materials, low CO yield and low CO conversion rate in the process of preparing solar thermal chemical fuel (two-step CO2 catalytic cracking); and provides Y 0.4 Sr 0.6 MnO3 perovskite porous support material and its synthesis method and application. The present invention increases the gas-solid reaction area, radiation absorption performance, heating rate and photothermal conversion efficiency by attaching high-performance catalytic materials into a porous structure.

[0008] The present invention prepares a porous skeleton-loaded novel oxygen carrier material to improve CO2 conversion rate and cycle stability. The present invention proposes a perovskite synthesis strategy that can achieve performance regulation; prepares a high-efficiency and extremely stable Y 0.4 Sr 0.6 MnO3 perovskite material; a method for preparing a porous medium structure is proposed to improve the overall efficiency from two aspects: the performance of the material itself and the attachment of the porous structure.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] The present invention aims to solve the technical problem that existing solar thermochemical materials cannot improve CO yield and CO2 conversion rate while maintaining high stability, and provides a method for preparing a high-performance perovskite porous support material.

[0011] In order to solve the above technical problems, Y 0.4 Sr 0.6 The MnO3 high performance perovskite porous loading material is prepared according to the following steps:

[0012] Step 1: Mix EDTA and ammonia solution, add deionized water to prepare a mixed solution, heat it in a water bath and stir it magnetically; while keeping the water bath heating and magnetic stirring, add Y(NO3)3·6H2O, Mn(NO3)2·4H2O and Sr(NO3)2 powder to the mixed solution, and then add citric acid monohydrate; add ammonia water to adjust the pH value, and keep heating and stirring for a certain time to obtain a gel;

[0013] Step 2: For Y obtained in step 1 0.4 Sr 0.6 The MnO3 gel is dried, the powdery substance obtained is ground, and then placed in a muffle furnace for calcination, and then ground to obtain Y 0.4 Sr 0.6 MnO3 powder;

[0014] Step 3: Use the Y obtained in step 2 0.4 Sr 0.6 MnO3 powder was mixed with deionized water, and the suspension was dropped onto the SiC porous skeleton, and then the attached porous skeleton was purged with an ear-cleaning bulb; and then dried to obtain Y 0.4 Sr 0.6 MnO3 perovskite porous support material.

[0015] It is further defined that the molar ratio of EDTA to ammonia water in step 1 is 1:2.

[0016] It is further defined that in step 1, deionized water is added to a total volume of 100 mL to 150 mL.

[0017] It is further defined that the water bath heating temperature in step 1 is 80° C. to 85° C., and the magnetic stirring speed is 300 rpm to 400 rpm.

[0018] It is further defined that the molar ratio of the metal nitrate, citric acid monohydrate and EDTA added in step 1 is 1:1.5:1.

[0019] It is further defined that in step 1, the molar ratio of Y(NO3)3·6H2O, Mn(NO3)2·4H2O and Sr(NO3)2 is 2:5:3.

[0020] It is further defined that the pH value in step 1 is 6-8, and the heating and stirring time is 20h-30h.

[0021] It is further defined that the drying temperature in step 2 is 110° C. to 130° C., and the drying time is 24 h to 30 h.

[0022] It is further defined that the temperature and time conditions for the muffle furnace calcination in step 2 should be 450°C for 4 hours, 1300°C for 20 hours, and 1400°C for 4 hours, and the heating rate is 5°C / min.

[0023] Further limit, in step 3, Y 0.4 Sr 0.6 The mass ratio of MnO3 powder to deionized water is 1:(0.75-1.5).

[0024] Further defined, in step 3, the pore density of the SiC porous skeleton is 10 ppi to 20 ppi, Y 0.4 Sr 0.6 The mass ratio of MnO3 powder to porous skeleton is 1:(2.4-2.5).

[0025] It is further defined that the drying temperature in step three is 110-130° C. and the drying time is 20-30 hours.

[0026] Aiming at the solar thermochemical CO2 catalytic cracking process and applying it to solar high temperature reactor, a Y with excellent thermochemical properties such as strong stability, high CO yield and high CO2 conversion rate is proposed. 0.4 Sr 0.6 MnO3 high-performance perovskite material. Based on the sol-gel method and the infiltration and adhesion method, a material synthesis strategy and a preparation method loaded on SiC porous structure are proposed.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Y used in the present invention 0.4 Sr 0.6The method for preparing MnO3 powder is to uniformly distribute the elements due to continuous stirring before gel formation. The temperature segmentation setting of the muffle furnace program is conducive to the decomposition of nitrates and improves the uniformity of doping. The proposed method can adjust the type and proportion of metal nitrates in the precursor according to actual needs to synthesize other doped perovskite materials, thereby realizing the thermochemical performance regulation and optimization design of the materials.

[0029] (2) Y proposed in the present invention 0.4 Sr 0.6 MnO3 powder material has relatively good CO2 cracking performance (high CO yield and total output) and can maintain stability in multiple cycles.

[0030] (3) The present invention is achieved by 0.4 Sr 0.6 The MnO3 powder material is attached to the SiC porous skeleton. On the one hand, it enhances the gas-solid reaction contact area between the powder material and CO2, and improves the redox reaction rate; on the other hand, benefiting from the strong radiation absorption performance of the porous structure, the material's heating rate is accelerated, the photothermal conversion efficiency, and the overall efficiency are improved. In addition, the proposed attachment method can replace the porous skeleton according to the needs of the solar thermal chemical system to achieve practical applications in different scenarios.

[0031] In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the attached drawings are only provided for reference and illustration and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Yes 0.4 Sr 0.6 MnO3 porous support material;

[0033] Figure 2 Yes 0.4 Sr 0.6 EDS results of MnO3 porous support material (element distribution is uniform);

[0034] Figure 3 It is a solar thermochemical CO2 catalytic cracking system. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, and do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0036] Specific implementation method 1: In this implementation method, Y 0.4 Sr 0.6 The MnO3 high performance perovskite porous loading material is prepared according to the following steps:

[0037] Step 1: Mix 15.29 g of EDTA with 7.12 g of 25 wt% ammonia solution, add deionized water to 100 mL to prepare the mixed solution, heat it in a water bath at 80 ° C and stir it magnetically at a speed of 400 rpm; while keeping the water bath heating and magnetic stirring, add 4.01 g, 6.57 g, and 3.32 g of Y(NO3)3·6H2O, Mn(NO3)2·4H2O, and Sr(NO3)2 powder respectively, then add 16.50 g of citric acid monohydrate, add ammonia water to adjust the pH value to 6, and keep heating and stirring for 24 hours to obtain Y 0.4 Sr 0.6 MnO3 gel;

[0038] Step 2: For Y obtained in step 1 0.4 Sr 0.6 The MnO3 gel was dried, and the powdery substance was ground and then placed in a muffle furnace with a heating rate of 5°C / min. It was calcined at 450°C for 4 hours, then heated to 1300°C for 20 hours, and then heated to 1400°C for 4 hours. Then, it was ground to obtain Y 0.4 Sr 0.6 MnO3 powder, multiple preparation of Y 0.4 Sr 0.6 MnO3 powder to make its mass greater than 20g;

[0039] Step 3: Weigh the Y obtained in step 2 0.4 Sr 0.6 20g of MnO3 powder was mixed with 15ml of deionized water, and the suspension was dropped onto a cylindrical SiC porous framework with a diameter of 60mm and a thickness of 40mm, and the pore size was 10ppi. The porous framework was then purged with an ear-cleaning bulb; the obtained porous framework was dried at 120℃ for 24h to obtain Y 0.4 Sr 0.6 MnO3 perovskite porous support material.

[0040] Figure 2 It can be seen that the elements are evenly distributed.

[0041] Thermogravimetric analysis was used to determine the 0.4 Sr 0.6Thermochemical CO2 catalytic cracking performance of MnO3 powder material. The CO production can be calculated by three-cycle experimental results at a reduction temperature of 1400℃ and an oxidation temperature of 1100℃ as shown in the following table. The results show that the material proposed in the present invention has strong stability, and the highest single-cycle CO production is 407.50μmol / g, and the total production of three cycles can reach 1040.63μmol / g.

[0042]

[0043] Determination of Y using solar thermochemical system experiments 0.4 Sr 0.6 The performance of MnO3 porous support material is shown in Figure 3.

[0044] The system consists of a solar simulator, a gas circuit, a reactor, an exhaust gas analysis device, and porous materials. 0.4 Sr 0.6 The MnO3 porous support material is placed in the reactor, and the temperature of the porous material is adjusted by adjusting the power of the solar simulator to carry out the redox reaction. The temperature is controlled to 1000℃ in the reduction stage under 400sccm Ar atmosphere, and the temperature is controlled to 900℃ in the oxidation stage under 200sccm CO2 and 200sccm Ar atmosphere. The high thermochemical properties of the proposed material are proved to achieve the expected effect by analyzing the content of each gas component in the tail gas. In a total of eleven sets of cycle experiments, the average maximum CO yield can reach 69.97mL / min, and the difference in the maximum CO yield of two adjacent cycles is as low as 3.04mL / min between the tenth and eleventh cycles, which proves its good stability.

[0045] The above describes the specific embodiments of the present invention. It should be noted that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essential content of the present invention.

Claims

1. Y 0.4 Sr 0.6 The method for synthesizing MnO3 perovskite porous support material is characterized in that: The following steps are involved: Step 1: Mix EDTA and ammonia solution, add deionized water, heat in a water bath under magnetic stirring, add Y(NO3)3·6H2O, Mn(NO3)2·4H2O and Sr(NO3)2 powders while maintaining water bath heating and magnetic stirring, then add citric acid monohydrate, add ammonia water to adjust the pH value, and keep heating and stirring for a certain period of time to obtain Y 0.4 Sr 0.6 MnO3 gel; Step 2: For Y obtained in step 1 0.4 Sr 0.6 The MnO3 gel is dried, ground, calcined, and ground again to obtain Y 0.4 Sr 0.6 MnO3 powder; Step 3: Use the Y obtained in step 2 0.4 Sr 0.6 MnO3 powder was mixed with deionized water and then dropped onto the SiC porous skeleton. After blowing and drying, Y 0.4 Sr 0.6 MnO3 perovskite porous support material.

2. The method according to claim 1, characterized in that: In step 1, the molar ratio of EDTA to ammonia water is 1:

2.

3. The method according to claim 1, characterized in that: In step 1, the water bath heating temperature is 80° C. to 85° C., and the magnetic stirring speed is 300 rpm to 400 rpm.

4. The method according to claim 1, characterized in that: In step 1, the molar ratio of the total molar amount of metal nitrate to citric acid monohydrate and EDTA is 1:1.5:1; the molar ratio of Y(NO3)3·6H2O, Mn(NO3)2·4H2O and Sr(NO3)2 is 2:5:

3.

5. The method according to claim 1, characterized in that: In step 1, the pH value is adjusted to 6-8, and the heating and stirring time is 20h-30h.

6. The method according to claim 1, characterized in that: In step 2, the drying temperature is 110° C. to 130° C., and the drying time is 24 h to 30 h.

7. The method according to claim 1, characterized in that: In step 2, the calcination process is as follows: the temperature is raised to 450°C at a rate of 5°C / min, and the temperature is kept at 450°C for 4 hours; the temperature is then raised to 1300°C at a rate of 5°C / min, and the temperature is kept at 1300°C for 20 hours; the temperature is then raised to 1400°C at a rate of 5°C / min, and the temperature is kept at 1400°C for 4 hours.

8. The method according to claim 1, characterized in that: Step 3 Y 0.4 Sr 0.6 The mass ratio of MnO3 powder to deionized water is 1:(0.75-1.5); the pore density of the SiC porous skeleton is 10ppi-20ppi, and Y 0.4 Sr 0.6 The mass ratio of MnO3 powder to porous skeleton is 1:(2.4-2.5); the drying temperature in step 3 is 110°C-130°C, and the drying time is 20h-30h.

9. Y prepared by any one of claims 1 to 8 0.4 Sr 0.6 MnO3 perovskite porous support material.

10. Y prepared by any one of claims 1 to 8 0.4 Sr 0.6 MnO3 perovskite porous support materials are used for solar thermochemical photothermal synergistic cracking of CO2.

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