Y 0.4 Sr 0.6 MnO3 perovskite porous support material, method of synthesis and use thereof

Abstract

This invention discloses Y 0.4 Sr 0.6 This invention relates to porous MnO3 perovskite supported materials, their synthesis method, and applications, belonging to the field of catalyst materials for CO2 fuel synthesis through cracking. The invention aims to solve the problems of low stability, low CO yield, and low CO2 conversion rate of catalytic materials in the two-step CO2 catalytic cracking process of solar thermochemical fuel preparation. The method involves mixing EDTA with an ammonia solution, adding deionized water, heating in a water bath, and magnetically stirring. Y(NO3)3·6H2O, Mn(NO3)2·4H2O, and Sr(NO3)2 powder are added, followed by citric acid monohydrate. Ammonia is added to adjust the pH value, while maintaining heating and stirring. The mixture is dried, ground, calcined, and then ground again. It is then mixed with deionized water, and the suspension is dropwise applied to a porous SiC framework and purged. The mixture is then dried. This invention utilizes Y... 0.4 Sr 0.6 The MnO3 powder material adheres to the porous SiC framework, which enhances the gas-solid reaction contact area between the powder material and CO2, thereby increasing the redox reaction rate. The heating rate of the material is accelerated, and the photothermal conversion efficiency and overall efficiency are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of solar thermochemical photocatalytic CO2 cracking catalyst materials, in particular, relates to a Y 0.4 Sr 0.6 MnO3 perovskite porous support material and a synthesis method and application thereof. BACKGROUND

[0002] Solar thermochemical CO2 catalytic cracking technology can convert solar energy into chemical energy, realize effective utilization of renewable energy, and reduce the content of CO2 in the atmosphere, thereby alleviating the greenhouse effect. The two-step method is a redox reaction of the catalyst at high temperature, and the reaction equation is as shown below:

[0003]

[0004] The efficiency of the catalyst in the reaction process affects the overall efficiency of the thermochemical fuel preparation to some extent. The application focuses on the ABO3 perovskite material with the general formula, which is considered to be the most potential, and prepares a high-efficiency Y 0.4 Sr 0.6 MnO3 catalyst, and proposes a suitable synthesis strategy. In addition, considering that the powder material is difficult to be directly applied to the solar reactor, a synthesis method of attaching to the SiC porous skeleton is proposed to improve the overall efficiency of the solar thermochemical CO2 catalytic cracking system.

[0005] The catalyst materials currently applied to solar thermochemical CO2 catalytic cracking mainly have the following three common problems: (1) the CO yield is not high and the reaction rate is low due to the reaction kinetics limitation; (2) the high temperature involved in the solar thermochemical CO2 cracking technology easily causes sintering of the material and reduces the stability; (3) the gas-solid reaction efficiency is affected by the contact area, and how to improve the contact area between the material and CO2 still faces challenges.

[0006] Therefore, it is particularly important to develop a high-performance (CO yield is improved while maintaining sufficient stability) porous support material. SUMMARY

[0007] The application solves the problems of low stability, low CO yield and low CO2 conversion rate of the catalytic material in the process of solar thermochemical fuel preparation (two-step CO2 catalytic cracking), and provides a Y 0.4 Sr 0.6 MnO3 perovskite porous support material and a synthesis method and application thereof. The application increases the gas-solid reaction area by attaching the high-performance catalytic material to the porous structure, increases the radiation absorption performance, improves the heating rate, and increases the light-thermal conversion efficiency.

[0008] The application prepares a porous framework loaded novel oxygen carrier material, improves CO2 conversion rate and cycle stability. The application provides a perovskite synthesis strategy which can realize performance regulation; prepares a Y 0.4 Sr 0.6 MnO3 perovskite material with high efficiency and excellent stability; and provides a porous medium structure preparation method, which improves the overall efficiency from the performance of the material itself and the attachment of the porous structure.

[0009] In order to achieve the above technical problems, the application adopts the following technical solutions:

[0010] The application solves the technical problem that the existing solar thermochemical material cannot improve the CO yield and CO2 conversion rate while maintaining high stability, and provides a preparation method of a high-performance perovskite porous loaded material.

[0011] In order to solve the above technical problems, the Y 0.4 Sr 0.6 The high-performance perovskite porous loaded material of Y

[0012] Step one, mix EDTA and ammonia solution, and add deionized water to configure a mixed solution, heat the mixed solution in a water bath and perform magnetic stirring; while maintaining 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; adjust the PH value by adding ammonia water, and maintain heating and stirring for a certain period of time to obtain a gel;

[0013] Step two, dry the Y 0.4 Sr 0.6 MnO3 gel obtained in step one, grind the obtained powder, and then place it in a muffle furnace for calcination, and then grind to obtain Y 0.4 Sr 0.6 MnO3 powder;

[0014] Step three, mix the Y 0.4 Sr 0.6 MnO3 powder obtained in step two with deionized water, drop the suspension onto a SiC porous framework, and then use an ear cleaning ball to blow the attached porous framework; dry it to obtain a Y 0.4 Sr 0.6 MnO3 perovskite porous loaded material.

[0015] Further limited, the molar ratio of EDTA and ammonia water in step one is 1:2.

[0016] Further limited, deionized water is added to a total volume of 100mL-150mL in step one.

[0017] Further limit, the water bath heating temperature of step one is 80-85 DEG C, and the magnetic stirring speed is 300-400 rpm.

[0018] Further limit, the molar ratio of metal nitrate, monohydrate citric acid and EDTA added in step one is 1:1.5:1.

[0019] Further limit, the molar ratio of Y(NO3)3.6H2O, Mn(NO3)2.4H2O and Sr(NO3)2 in step one is 2:5:3.

[0020] Further limit, the PH value of step one is 6-8, and the heating and stirring time is 20-30 h.

[0021] Further limit, the drying temperature of step two is 110-130 DEG C, and the drying time is 24-30 h.

[0022] Further limit, the temperature and time conditions of muffle furnace calcination in step two should be 450 DEG C for 4 h, 1300 DEG C for 20 h, and 1400 DEG C for 4 h, and the heating rate is all 5 DEG C / min.

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

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

[0025] Further limit, the drying temperature of step three is 110-130 DEG C, and the drying time is 20-30 h.

[0026] For the process of solar thermochemical CO2 catalytic cracking, aiming at being applied to solar high-temperature reactor, a Y 0.4 Sr 0.6 MnO3 high-performance perovskite material with excellent thermochemical properties such as strong stability, high CO yield and high CO2 conversion rate is provided. A material synthesis strategy based on sol-gel method and infiltration adhesion method and a preparation method of loading on SiC porous structure are provided.

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

[0028] (1) The Y 0.4 Sr 0.6The MnO3 powder preparation method makes the elements uniformly distributed due to continuous stirring before gel formation. The temperature segmentation of the muffle furnace program is beneficial to the decomposition of the nitrate and improves the doping uniformity. The proposed method can adjust the types and proportions of metal nitrates in the precursor according to actual needs to synthesize other doped perovskite materials, and realize the thermodynamic performance control and optimal design of the materials.

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

[0030] (3) The Y 0.4 Sr 0.6 The MnO3 powder material is attached to the SiC porous skeleton, which on the one hand enhances the gas-solid reaction contact area of the powder material and CO2, and improves the redox reaction rate; on the other hand, benefits from the strong radiation absorption performance of the porous structure, the material heating rate is accelerated, the photo-thermal 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 thermochemical system to realize practical application in different scenarios.

[0031] In order to further understand the features and technical contents of the present application, please refer to the following detailed description of the present application and the accompanying drawings, however, the accompanying drawings are provided for reference and illustration only, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is Y 0.4 Sr 0.6 MnO3 porous loaded material;

[0033] Figure 2 is Y 0.4 Sr 0.6 EDS results of the Y

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

[0035] The present application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the present application, and do not limit the present application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application.

[0036] Specific implementation one: in this embodiment, Y 0.4 Sr 0.6 MnO3 high-performance perovskite porous support material is prepared according to the following steps:

[0037] Step one, 15.29 g of EDTA is mixed with 7.12 g of 25 wt% ammonia water solution, and deionized water is added to 100 ml to configure a mixed solution, which is heated in a water bath at 80°C and magnetically stirred at a speed of 400 rpm; while maintaining the water bath heating and magnetic stirring, 4.01 g of Y(NO3)3·6H2O, 6.57 g of Mn(NO3)2·4H2O and 3.32 g of Sr(NO3)2 powder are added, then 16.50 g of citric acid monohydrate is added, ammonia water is added to adjust the pH value to 6, and heating and stirring are maintained for 24 h to obtain Y 0.4 Sr 0.6 MnO3 gel;

[0038] Step two, the Y 0.4 Sr 0.6 MnO3 gel obtained in step one is dried, the obtained powder is ground, and then placed in a muffle furnace with a controlled heating rate of 5°C / min, calcined at 450°C for 4h, then heated to 1300°C and calcined for 20h, then heated to 1400°C and calcined for 4h, and then ground to obtain Y 0.4 Sr 0.6 MnO3 powder, Y 0.4 Sr 0.6 MnO3 powder is prepared multiple times, and the mass of Y

[0039] Step three, 20 g of Y 0.4 Sr 0.6 MnO3 powder obtained in step two is mixed with 15 ml of deionized water, and the suspension is dropped onto a cylindrical SiC porous skeleton with a diameter of 60 mm and a thickness of 40 mm, the pore size of which is 10 ppi, and then the porous skeleton after attachment is blown by an ear cleaning ball; the obtained porous skeleton is dried at 120°C 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 uniformly distributed.

[0041] The Y 0.4 Sr 0.6The thermochemical CO2catalytic cracking performance of the MnO3powder material. The CO production of three-cycle experiments at 1400℃ reduction temperature and 1100℃ oxidation temperature is shown in the following table by calculation. The results show that the material proposed in the application 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] The solar thermochemical system experiment is used to determine Y 0.4 Sr 0.6 The performance of the MnO3porous support material, and a schematic diagram thereof is shown in 3.

[0044] The system is composed of a solar simulator, a gas circuit, a reactor, a tail gas analysis device, and a porous material. During the experiment, the prepared high-performance Y 0.4 Sr 0.6 The MnO3porous 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 perform the oxidation-reduction reaction. In the reduction stage, the temperature is controlled at 1000℃ under an Ar atmosphere of 400sccm, and in the oxidation stage, the temperature is controlled at 900℃ under a CO2 atmosphere of 200sccm and an Ar atmosphere of 200sccm. By analyzing the gas component content in the tail gas, it is proved that the high thermochemical performance of the material proposed achieves the expected effect. In a total of eleven cycles of experiments, the average maximum CO production can reach 69.97mL / min, and the difference between the maximum CO production of adjacent two cycles is as low as 3.04mL / min between the tenth and eleventh cycles, which proves that it has good stability.

[0045] The specific embodiments of the application are described above. It should be pointed out that the application is not limited to the above specific embodiments, and those skilled in the art can make various modifications or modifications within the scope of the claims, which does not affect the essential content of the application.

Claims

1. A kind The application of perovskite porous load materials is characterized by, The The preparation process of perovskite porous supported materials is as follows: Step 1: Mix EDTA with an ammonia solution, add deionized water, and heat in a water bath with magnetic stirring. While maintaining water bath heating and magnetic stirring, add... , and The powder is then mixed with citric acid monohydrate, and ammonia is added to adjust the pH value. Heating and stirring are maintained for a certain period of time to obtain the desired product. gel; The molar ratio of EDTA to ammonia is 1:2; The water bath heating temperature is 80℃~85℃, and the magnetic stirring speed is 300 rpm~400 rpm; The total molar ratio of metal nitrates to citric acid monohydrate and EDTA is 1:1.5:1; , and The molar ratio is 2:5:3; The pH value was adjusted to 6-8, and the heating and stirring time was 20-30 h. Step 2: Analyze the results obtained in Step 1. The gel is dried, ground, calcined, and then ground again to obtain Y. 0.4 Sr 0.6 MnO3 powder; The drying temperature is 110 ℃~130 ℃, and the drying time is 24 h~30 h; Calcination process: The temperature is increased to 450 ℃ at a rate of 5 ℃ / min and held for 4 h. Then the temperature is increased to 1300 ℃ at a rate of 5 ℃ / min and held for 20 h. Finally, the temperature is increased to 1400 ℃ at a rate of 5 ℃ / min and held for 4 h. Step 3: Use the information obtained in Step 2 The powder is mixed evenly with deionized water, then dropped onto a porous SiC framework, purged, and dried to obtain the desired product. Perovskite porous load-bearing materials; The powder to deionized water mass ratio is 1:(0.75~1.5); the SiC porous framework pore density is 10 ppi~20 ppi. The mass ratio of powder to porous framework is 1:(2.4~2.5); the drying temperature in step three is 110℃~130℃, and the drying time is 20 h~30 h; The Perovskite porous supported materials for solar thermochemical-photothermal synergistic pyrolysis .

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