A thermoelectric catalytic material for CO2 exhaust gas treatment and a preparation method thereof

Abstract

The application discloses a thermoelectric catalytic material for CO2 waste gas treatment and a preparation method thereof. 3‑x Tb x Co4O9 base material; three, after the Ca 3‑x Tb x Co4O9 base material is ball milled to obtain a Ca 3‑x Tb x Co4O9 preform; four, solid phase sintering forming obtains Ca 3‑x Tb x Co4O9 thermoelectric catalytic material. 3‑x Tb x Co4O9 thermoelectric catalytic material; the Ca 3‑x Tb x Co4O9 thermoelectric catalytic material has high thermal stability and high catalytic efficiency, realizes extremely high CO2 waste gas conversion rate and adjustable product selectivity, and has the advantages of simple preparation process, low cost and no pollution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of powder metallurgy and thermoelectric catalysis, and particularly relates to a thermoelectric catalytic material for CO2 waste gas treatment and a preparation method thereof. BACKGROUND

[0002] At present, the rapid expansion of energy demand exacerbates environmental pollution, especially the smelting, thermal power, automobile and other high energy consumption industries are accompanied by high emissions of waste heat and CO2 waste gas, which significantly increases the environmental governance cost. Therefore, it is imminent to explore new energy conversion technology, and to invent environmentally friendly and efficient catalysts is the key to the post-treatment of waste heat and waste gas in the energy conversion process. In recent years, studies have shown that thermoelectric effect can improve catalytic efficiency, and thus a new concept of thermoelectric catalysis has been proposed. In the energy conversion process, thermoelectric materials act as catalyst carriers and promoters, converting the temperature gradient distributed on the material into a potential difference, which can activate chemical reactions at lower temperatures, speed up reaction rates, and even change the selectivity of reaction products. Especially, low-cost Ca3Co4O9 type thermoelectric catalytic materials have outstanding efficiency advantages in the conversion of CO2 waste gas.

[0003] At present, the research on Ca3Co4O9 type thermoelectric materials in China is very limited. The patent with the application number CN202211350329.1 “Calcium cobaltate thermoelectric ceramic with directional micro-nano through holes and preparation method thereof” discloses a preparation method for successfully preparing directional through hole Ca3Co4O9 based thermoelectric ceramic material by freeze casting technology, which has the advantages of simple steps, environmental protection and economy, and the pore size is easy to control. However, the freeze casting technology is difficult to realize the efficient and rapid separation of the solidification medium from the blank, and the prepared material has anisotropy, and the patent does not mention the application of Ca3Co4O9 type thermoelectric materials.

[0004] The application of thermoelectric materials in catalysis has been reported abroad. In the literature “A. Achour, Tuning of catalytic activity by thermoelectric materials for carbon dioxide hydrogenation, Advanced Energy Materials 8 (2018) 701430”, a thermoelectric material BiCuSeO was first reported to exhibit thermoelectric catalytic effect in CO2 reduction reaction, which changed the chemical equilibrium, not only improved the reaction rate, but also affected the product selection, and realized the conversion of CO2 to CO+H2O in CO2 reduction reaction, and the product had high CO selectivity. However, the BiCuSeO thermoelectric catalytic material prepared in the literature report was unstable and easily decomposed when the temperature was higher than 500℃.

[0005] The application of thermoelectric materials in catalysis has been reported abroad. In the literature "A. Achour, Tuning of catalytic activity by thermoelectric materials for carbon dioxide hydrogenation, Advanced Energy Materials 8 (2018) 701430", a thermoelectric material BiCuSeO was first reported to exhibit thermoelectric catalytic effect in CO2 reduction reaction, which changed the chemical equilibrium, not only improved the reaction rate, but also affected the product selection, and realized the conversion of CO2 to CO+H2O in CO2 reduction reaction, and the product had high CO selectivity. However, the BiCuSeO thermoelectric catalytic material prepared in the literature report was poor in stability at a temperature higher than 500 DEG C, and was easily decomposed and failed.

[0006] The patent "Tuning of catalytic activity by thermoelectric materials: GB2017 / 053361" with application number WO2018087540A1 proposes a scheme of sputtering a thin film of noble metal Pt catalyst on the surface of bulk thermoelectric material BiCuSeO, and they use the prepared composite catalyst material for catalyzing the oxidation reaction of C2H4, and the results show that the thermoelectric effect greatly improves the catalytic performance of Pt catalyst and greatly improves the reaction rate. However, the material used in this patent contains noble metal material with high cost, which is not conducive to large-scale application.

[0007] In view of the fact that the catalysts used in industry are usually in high temperature working environment, which puts strict test on the stability and service life of the catalyst material. In order to further expand the service temperature of thermoelectric catalytic material to more than 500 DEG C, and effectively improve the conversion rate of CO2 exhaust gas, it is necessary to improve the thermoelectric performance and thermal stability of the thermoelectric material by doping modification. At present, the only thermoelectric catalytic material of BiCuSeO and Bi2Te3 has a service temperature lower than 500 DEG C, which cannot provide reference. Therefore, it is necessary to propose a new Ca 3-x Tb x Co4O9 thermoelectric catalytic material composition and its preparation method, and realize engineering application. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a preparation method of thermoelectric catalytic material for CO2 exhaust treatment, which solves the above problems of the prior art. The method adopts the process of hot sintering and solid phase sintering forming, and obtains Ca 3-x Tbx Co4O9 thermoelectric catalytic material, the Ca 3-x Tb x The Co4O9 thermoelectric catalytic material has high thermal stability and high catalytic efficiency, and simultaneously realizes extremely high CO2 waste gas conversion rate and adjustable product selectivity, and solves the problems of low use temperature and poor thermal stability of existing thermoelectric catalytic materials.

[0009] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a preparation method of a thermoelectric catalytic material for CO2 waste gas treatment, characterized in that the method comprises the following steps:

[0010] Step one, raw material powder mixing: taking CaO powder, Co3O4 powder and Tb4O7 powder with mass purity greater than 99% as raw materials, weighing the raw materials according to the stoichiometric ratio of the target product Ca 3-x Tb x Co4O9, wherein 0≤x≤0.5, pouring the weighed raw material powder into a corundum ball mill jar and placing corundum grinding balls in it, then flushing argon protection into the corundum ball mill jar and sealing it, and placing it in a planetary ball mill for ball milling to obtain a mixed powder;

[0011] Step two, preparing Ca 3-x Tb x Co4O9 base material by heat sintering method: heat sintering the mixed powder obtained in step one, and taking out to obtain a blocky Ca 3-x Tb x Co4O9 base material;

[0012] Step three, cold pressing: placing the blocky Ca 3-x Tb x Co4O9 base material obtained in step two into a corundum ball mill jar and placing corundum grinding balls in it, then flushing argon protection into the corundum ball mill jar and sealing it, and placing it in a planetary ball mill for ball milling to obtain a preform powder, filling the preform powder into a mold for cold pressing to obtain a Ca 3-x Tb x Co4O9 preform;

[0013] Step four, solid phase sintering forming: placing the Ca 3-x Tb x Co4O9 preform obtained in step three in a tube furnace for solid phase sintering forming to obtain a Ca 3-x Tb x Co4O9 thermoelectric catalytic material.

[0014] The preparation method of the thermoelectric catalytic material for CO2 waste gas treatment has the characteristics that the ball-to-material ratio of the ball milling in step one is 20:1, the rotating speed is 450 rpm, and the ball milling time is 2 h. The mixed powder obtained by using the ball milling process is more uniform and does not have the powder clustering phenomenon.

[0015] The preparation method of the thermoelectric catalytic material for CO2 waste gas treatment has the characteristics that the process of the hot sintering in step two is that the mixed powder is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and the temperature is raised to 300 DEG C at a rate of 15 DEG C / min and kept for 10 min, then raised to 700 DEG C at a rate of 10 DEG C / min and kept for 10 min, and finally raised to 750 DEG C-950 DEG C at a rate of 5 DEG C / min and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained hot sintered material is manually broken and ground, reloaded into a cylindrical alumina crucible and manually compacted, and then placed in a box-type resistance furnace, and the temperature is raised to 700 DEG C at a rate of 10 DEG C / min and kept for 10 min, and then raised to 750 DEG C-950 DEG C at a rate of 5 DEG C / min and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained blocky Ca 3-x Tb x Co4O9 base material.

[0016] The two-stage hot sintering process is adopted, the mixed powder is fully combined with oxygen in the sintering atmosphere, i.e. the atmospheric environment, the problem of insufficient oxygen in the raw material is completely solved, the blocky Ca 3-x Tb x Co4O9 base material is obtained, and the purity of the Ca

[0017] The preparation method of the thermoelectric catalytic material for CO2 waste gas treatment has the characteristics that the ball-to-material ratio of the ball milling in step three is 20:1, the rotating speed is 350 rpm, and the ball milling time is 1 h. The preform powder obtained under the ball milling parameters is more uniform and does not have the powder clustering phenomenon.

[0018] The preparation method of the thermoelectric catalytic material for CO2 waste gas treatment has the characteristics that in step three, the preform powder is loaded into a 316 stainless steel mold with a size of φ20 mm*6 mm, the mold is vibrated while loading, and then the loaded mold is placed on the powder tablet press platform and cold-pressed at a pressure of 150 MPa to form a Ca 3-x Tb x Co4O9 preform.

[0019] The preparation method of the thermoelectric catalytic material for CO2 waste gas treatment has the characteristics that the process of the solid phase sintering forming in the fourth step is: using the stepwise heating mode, heating to 300 DEG C at the rate of 15 DEG C / min and keeping for 10 min, then heating to 800 DEG C at the rate of 10 DEG C / min and keeping for 10 min, finally heating to 850 DEG C-1000 DEG C at the rate of 5 DEG C / min and keeping for 20 h, and then cooling to room temperature with the furnace.

[0020] In addition, the application further discloses a thermoelectric catalytic material for CO2 waste gas treatment.

[0021] Compared with the prior art, the application has the following advantages:

[0022] 1. The application adopts the process of combining the hot sintering method with the solid phase sintering forming, and the quality purity and the Ca 3-x Tb x Co4O9 thermoelectric catalytic material are obtained by controlling the temperature of the hot sintering method and the solid phase sintering forming, so that the catalytic activity and the catalytic efficiency of the Ca 3- x Tb x Co4O9 thermoelectric catalytic material are improved.

[0023] 2. The Ca 3-x Tb x Co4O9 thermoelectric catalytic material is obtained by doping the Tb element, and the Ca 3- x Tb x Co4O9 thermoelectric catalytic material is effectively improved. 3-x Tb x Co4O9 thermoelectric catalytic material has excellent thermal stability, and the service life at 800 DEG C is more than 200 h.

[0024] 3. The Ca 3-x Tb x Co4O9 thermoelectric catalytic material prepared by the application has excellent thermoelectric catalytic effect, the CO2 conversion rate at 435 DEG C is 64%, which is close to the theoretical limit of the conversion efficiency, and the cooling speed of the material surface is adjusted by replacing the cooling medium such as air, water, liquid nitrogen and liquid helium, which makes the cooling speed of the material surface increase, so that the CO selectivity in the product is greatly changed, and the minimum CO selectivity is 23%.

[0025] 4. The preparation process of the application is simple, and has the advantages of low cost and no pollution.

[0026] The technical solutions of the present application are described in further detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 CaCo4O9 prepared in Example 1 of the present application 2.6 Tb 0.4 A photograph of a Co4O9 thermoelectric catalytic material.

[0028] Figure 2 CaCo4O9 prepared in Example 1 of the present application 2.6 Tb 0.4 A graph of the results of a thermal stability test of a Co4O9 thermoelectric catalytic material.

[0029] Figure 3 CaCo4O9 prepared in Example 1 of the present application 2.6 Tb 0.4 A graph of the results of a phase detection of a Co4O9 thermoelectric catalytic material.

[0030] Figure 4 CaCo4O9 prepared in Example 1 of the present application 2.6 Tb 0.4 A graph comparing the results of a CO2 conversion rate test of a Co4O9 thermoelectric catalytic material with the theoretical conversion rate limit.

[0031] Figure 5 CaCo4O9 prepared in Example 1 of the present application 2.6 Tb 0.4 A graph comparing the CO selectivity of a catalytic product of a Co4O9 thermoelectric catalytic material under different cooling modes of the sample surface. DETAILED DESCRIPTION

[0032] Example 1

[0033] This example includes the following steps:

[0034] Step 1, raw material powder mixing: CaO powder, Co3O4 powder, and Tb4O7 powder with a mass purity of greater than 99% are used as raw materials, and the raw materials are weighed according to the stoichiometric ratio of the target product CaCo4O9, and the weighed raw material powder is poured into a corundum ball mill jar and corundum grinding balls are added according to a ball-to-material ratio of 20:1. The corundum ball mill jar is then flushed with argon gas for protection and sealed, and placed in a planetary ball mill for ball milling at a speed of 450 rpm for 2 h to obtain a mixed powder. 2.6 Tb 0.4

[0035] Step 2, preparation of CaCo4O9 by thermal sintering 2.6 Tb 0.4 ​Co4O9 base material: the mixed powder obtained in step one was loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and heated at a rate of 15 ℃ / min to 300 ℃ and kept for 10 min, then heated at a rate of 10 ℃ / min to 700 ℃ and kept for 10 min, and finally heated at a rate of 5 ℃ / min to 850 ℃ and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained hot sintered material was taken out and manually crushed and ground, reloaded into a cylindrical alumina crucible and manually compacted, and then placed in a box-type resistance furnace, and heated at a rate of 10 ℃ / min to 700 ℃ and kept for 10 min, and then heated at a rate of 5 ℃ / min to 850 ℃ and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained blocky Ca 2.6 Tb 0.4 Co4O9 base material;

[0036] Step three, cold-pressed green body: the blocky Ca 2.6 Tb 0.4 Co4O9 base material was placed in an agate ball mill jar and agate grinding balls were added according to a ball-to-powder ratio of 20:1, then argon gas was flushed into the agate ball mill jar and sealed, and then placed in a planetary ball mill for ball milling at a speed of 350 rpm for 1 h to obtain a preform powder, which was loaded into a 316 stainless steel mold with a size of φ20 mm×6 mm, and the mold was vibrated while the material was continuously loaded, then the loaded mold was placed on the powder tablet press machine stage and cold-pressed at a pressure of 150 MPa with a deformation of 50%, and after demolding, a Ca 2.6 Tb 0.4 Co4O9 preform;

[0037] Step four, solid phase sintering: the Ca 2.6 Tb 0.4 Co4O9 preform obtained in step three was placed in a tube furnace for solid phase sintering, and heated at a rate of 15 ℃ / min to 300 ℃ and kept for 10 min, then heated at a rate of 10 ℃ / min to 800 ℃ and kept for 10 min, and finally heated at a rate of 5 ℃ / min to 850 ℃ and kept for 20 h, to obtain a Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material.

[0038] Figure 1 is the Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material prepared in this embodiment, and Figure 1 It can be seen that the Ca 2.6 Tb0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface.

[0039] Figure 2 Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface. Figure 2 It can be seen that the Ca 2.6 Tb 0.4 The weight gain of the Co4O9 thermoelectric catalytic material is only about 3%, and no other phase transition reaction is observed according to the exothermic peak, indicating that the Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has excellent thermal stability below 800 DEG C.

[0040] Figure 3 Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface. Figure 3 Only the Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface. 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface.

[0041] Figure 4 Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface. Figure 4 It can be seen that the Ca 2.6 Tb 0.4 The CO2 conversion rate of the Co4O9 thermoelectric catalytic material at 435 DEG C reaches 64%, which is close to the theoretical limit of conversion efficiency.

[0042] Figure 5 Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material has a size regulation and a smooth surface. Figure 4 It can be seen that when the cooling medium in contact with the surface of the material sample is air, the CO selectivity of the catalytic product at 300 DEG C is about 99%, and when the cooling medium in contact with the surface of the material sample is water, the CO selectivity of the catalytic product at 300 DEG C is about 23%, indicating that the Ca 2.6 Tb 0.4 The Co4O9 thermoelectric catalytic material can greatly change the CO selectivity of the product by changing the cooling medium in contact with the surface thereof.

[0043] Example 2

[0044] This example includes the following steps:

[0045] Step one, raw material mixed powder: CaO powder, Co3O4 powder, Tb4O7 powder with mass purity greater than 99% as raw materials, according to the stoichiometric ratio of Ca 2.6 Tb 0.4 Co4O9, the weighed raw material powder is poured into a agate ball mill jar and agate grinding balls are put in according to the ratio of 20:1, then argon protection is flushed into the agate ball mill jar and sealed, and then placed in a planetary ball mill for ball milling, the ball milling speed is 450 rpm, and the ball milling time is 2 h, to obtain a mixed powder;

[0046] Step two, preparation of Ca 2.6 Tb 0.4 Co4O9 master material by hot sintering method: the mixed powder obtained in step one is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating method is adopted, the temperature is raised to 300 ℃ at a rate of 15 ℃ / min and kept for 10 min, then the temperature is raised to 700 ℃ at a rate of 10 ℃ / min and kept for 10 min, finally the temperature is raised to 850 ℃ at a rate of 5 ℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, the obtained hot sintered material is taken out and manually broken and ground, reloaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating method is adopted, the temperature is raised to 700 ℃ at a rate of 10 ℃ / min and kept for 10 min, then the temperature is raised to 850 ℃ at a rate of 5 ℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, and the obtained bulk Ca 2.6 Tb 0.4 Co4O9 master material is taken out;

[0047] Step three, cold pressing: the bulk Ca 2.6 Tb 0.4 Co4O9 master material obtained in step two is placed in an agate ball mill jar and agate grinding balls are put in according to the ratio of 20:1, then argon protection is flushed into the agate ball mill jar and sealed, and then placed in a planetary ball mill for ball milling, the ball milling speed is 350 rpm, and the ball milling time is 1 h, to obtain a preform powder, the preform powder is filled into a 316 stainless steel mold with a size of φ20 mm×6 mm, and the mold is vibrated while filling, then the filled mold is placed on the powder tablet press machine stage, and cold pressing is performed under a pressure of 150 MPa, with a deformation of 50%, and a Ca 2.6 Tb 0.4 Co4O9 preform with a size of φ20 mm×3 mm is obtained after demolding;

[0048] Step four, solid phase sintering forming: the Ca 2.6 Tb 0.4 Co4O9 preform is placed in a tube furnace for solid phase sintering forming, and a staged heating mode is adopted, the temperature is raised to 300℃ at a rate of 15℃ / min and kept for 10min, then the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10min, finally the temperature is raised to 900℃ at a rate of 5℃ / min and kept for 20h, and then the furnace is cooled to room temperature, to obtain Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material.

[0049] Example 3

[0050] This example includes the following steps:

[0051] Step one, raw material powder mixing: CaO powder, Co3O4 powder and Tb4O7 powder with mass purity greater than 99% are used as raw materials, and the raw materials are weighed according to the stoichiometric ratio of the target product Ca 2.6 Tb 0.4 Co4O9, the weighed raw material powder is poured into a agate ball mill jar, and agate grinding balls are put in according to the ratio of 20:1, then argon protection is poured into the agate ball mill jar and sealed, and then the planetary ball mill is used for ball milling, the ball milling speed is 450rpm, and the ball milling time is 2h, to obtain a mixed powder;

[0052] Step two, preparing Ca 2.6 Tb 0.4 Co4O9 master material by hot sintering method: the mixed powder obtained in step one is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating mode is adopted, the temperature is raised to 300℃ at a rate of 15℃ / min and kept for 10min, then the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10min, finally the temperature is raised to 850℃ at a rate of 5℃ / min and kept for 20h, and then the furnace is cooled to room temperature, the obtained hot sintering material is taken out and manually crushed and ground, reloaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating mode is adopted, the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10min, then the temperature is raised to 850℃ at a rate of 5℃ / min and kept for 20h, and then the furnace is cooled to room temperature, and the obtained blocky Ca 2.6 Tb 0.4 Co4O9 master material;

[0053] Step three, cold pressing: the blocky Ca 2.6 Tb 0.4Co4O9 master batch is placed in a corundum ball mill jar and corundum grinding balls are put in the jar according to a ball-to-powder ratio of 20:1, then argon gas is flushed into the corundum ball mill jar and sealed, and the jar is placed in a planetary ball mill to perform ball milling at a rotation speed of 350 rpm for 1 h to obtain a preform powder, the preform powder is filled into a 316 stainless steel mold with a size of φ20 mm x 6 mm, and the mold is vibrated while the powder is continuously filled, then the filled mold is placed on a powder tablet press platform and cold-pressed at a pressure of 150 MPa to form a Ca 2.6 Tb 0.4 Co4O9 preform;

[0054] Step four, solid phase sintering: the Ca 2.6 Tb 0.4 The Co4O9 preform is placed in a tube furnace for solid phase sintering, and a stepwise heating method is adopted, i.e., the temperature is raised to 300℃ at a rate of 15℃ / min and kept for 10 min, then the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10 min, and finally the temperature is raised to 1000℃ at a rate of 5℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, to obtain a Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material.

[0055] Example 4

[0056] This example includes the following steps:

[0057] Step one, raw material powder mixing: CaO powder, Co3O4 powder and Tb4O7 powder with a mass purity of more than 99% are used as raw materials, and the raw materials are weighed according to the stoichiometric ratio of the target product Ca 2.6 Tb 0.4 Co4O9, the weighed raw material powder is poured into a corundum ball mill jar and corundum grinding balls are put in the jar according to a ball-to-powder ratio of 20:1, then argon gas is flushed into the corundum ball mill jar and sealed, and the jar is placed in a planetary ball mill to perform ball milling at a rotation speed of 450 rpm for 2 h to obtain a mixed powder;

[0058] Step two, preparation of Ca 2.6 Tb 0.4Co4O9 material: the mixed powder obtained in step one was loaded into a cylindrical alumina crucible and manually compacted, and then placed in a box-type resistance furnace, and heated at a rate of 15 ℃ / min to 300 ℃ and kept for 10 min, then heated at a rate of 10 ℃ / min to 700 ℃ and kept for 10 min, and finally heated at a rate of 5 ℃ / min to 750 ℃ and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained hot sintered material was taken out and manually crushed and ground, reloaded into a cylindrical alumina crucible and manually compacted, and then placed in a box-type resistance furnace, and heated at a rate of 10 ℃ / min to 700 ℃ and kept for 10 min, and then heated at a rate of 5 ℃ / min to 750 ℃ and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained blocky Ca 2.6 Tb 0.4 Co4O9 material;

[0059] Step three, cold-pressed green body: the blocky Ca 2.6 Tb 0.4 Co4O9 material was placed in an agate ball mill jar and agate grinding balls were added according to a ball-to-material ratio of 20:1, then argon gas protection was flushed into the agate ball mill jar and sealed, and then placed in a planetary ball mill for ball milling at a speed of 350 rpm for 1 h to obtain a preform powder, which was filled into a 316 stainless steel mold with a size of φ20 mm x 6 mm, and the mold was vibrated while the material was continuously filled, then the filled mold was placed on the powder tablet machine stage and cold-pressed at a pressure of 150 MPa, with a deformation of 50%, and after demolding, a Ca 2.6 Tb 0.4 Co4O9 preform;

[0060] Step four, solid phase sintering: the Ca 2.6 Tb 0.4 Co4O9 preform obtained in step three was placed in a tube furnace for solid phase sintering, and heated at a rate of 15 ℃ / min to 300 ℃ and kept for 10 min, then heated at a rate of 10 ℃ / min to 700 ℃ and kept for 10 min, and finally heated at a rate of 5 ℃ / min to 900 ℃ and kept for 20 h, and then cooled to room temperature with the furnace, to obtain a Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material.

[0061] Example 5

[0062] This example includes the following steps:

[0063] Step one, raw material mixed powder: CaO powder, Co3O4 powder, Tb4O7 powder with mass purity greater than 99% as raw materials, according to the stoichiometric ratio of Ca 2.6 Tb 0.4 Co4O9, the weighed raw material powder is poured into a agate ball mill tank and agate grinding balls are put in according to the ratio of 20:1, then argon protection is flushed into the agate ball mill tank and sealed, and placed in a planetary ball mill for ball milling, the ball milling speed is 450 rpm, and the ball milling time is 2 h, to obtain a mixed powder;

[0064] Step two, preparation of Ca 2.6 Tb 0.4 Co4O9 master material by hot sintering method: the mixed powder obtained in step one is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating method is adopted, the temperature is raised to 300℃ at a rate of 15℃ / min and kept for 10 min, then the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10 min, finally the temperature is raised to 950℃ at a rate of 5℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, the obtained hot sintered material is taken out and manually broken and ground, reloaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating method is adopted, the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10 min, then the temperature is raised to 950℃ at a rate of 5℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, and the obtained blocky Ca 2.6 Tb 0.4 Co4O9 master material is taken out;

[0065] Step three, cold pressing: the blocky Ca 2.6 Tb 0.4 Co4O9 master material obtained in step two is placed in an agate ball mill tank and agate grinding balls are put in according to the ratio of 20:1, then argon protection is flushed into the agate ball mill tank and sealed, and placed in a planetary ball mill for ball milling, the ball milling speed is 350 rpm, and the ball milling time is 1 h, to obtain a preform powder, the preform powder is filled into a 316 stainless steel mold with a filling area size of φ20mm×6mm, and the mold is vibrated while filling, then the filled mold is placed on the powder tablet press machine stage, and cold pressing is performed under a pressure of 150 MPa, with a deformation of 50%, and a Ca 2.6 Tb 0.4 Co4O9 preform with a size of φ20mm×3mm is obtained after demolding;

[0066] Step four, solid phase sintering: the Ca 2.6 Tb 0.4 Co4O9 preform obtained in step three is placed in a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, and a staged heating method is adopted, the temperature is raised to 700℃ at a rate of 10℃ / min and kept for 10 min, then the temperature is raised to 950℃ at a rate of 5℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, and the obtained CaThe Co4O9 preform is placed in a tube furnace for solid phase sintering forming, a staged heating mode is adopted, heating to 300 DEG C at a rate of 15 DEG C / min and keeping for 10 min, then heating to 700 DEG C at a rate of 10 DEG C / min and keeping for 10 min, finally heating to 900 DEG C at a rate of 5 DEG C / min and keeping for 20 h, and then cooling to room temperature with the furnace, to obtain Ca 2.6 Tb 0.4 Co4O9 thermoelectric catalytic material.

[0067] Example 6

[0068] The embodiment includes the following steps:

[0069] Step one, raw material mixed powder: CaO powder and Co3O4 powder with mass purity greater than 99% are used as raw materials, the raw materials are weighed according to the stoichiometric ratio of the target product Ca3Co4O9, the weighed raw material powder is poured into a agate ball mill jar, agate grinding balls are put in according to the ball to material ratio of 20:1, then argon protection is flushed into the agate ball mill jar and sealed, and the agate ball mill jar is placed in a planetary ball mill for ball milling, the ball milling speed is 450 rpm, and the ball milling time is 2 h, to obtain a mixed powder;

[0070] Step two, preparation of Ca3Co4O9 base material by hot sintering method: the mixed powder obtained in step one is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, a staged heating mode is adopted, heating to 300 DEG C at a rate of 15 DEG C / min and keeping for 10 min, then heating to 700 DEG C at a rate of 10 DEG C / min and keeping for 10 min, finally heating to 850 DEG C at a rate of 5 DEG C / min and keeping for 20 h, and then cooling to room temperature with the furnace, the obtained hot sintered material is taken out and manually crushed and ground, reloaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, a staged heating mode is adopted, heating to 700 DEG C at a rate of 10 DEG C / min and keeping for 10 min, then heating to 850 DEG C at a rate of 5 DEG C / min and keeping for 20 h, and then cooling to room temperature with the furnace, and the obtained blocky Ca3Co4O9 base material is taken out;

[0071] Step three, cold-pressing the green compact: the blocky Ca3Co4O9 master batch obtained in step two is placed in an agate ball mill jar and agate milling balls are put in the jar according to a ball-to-powder ratio of 20:1, then argon gas is flushed into the agate ball mill jar and the jar is sealed, and the jar is placed in a planetary ball mill to perform ball milling at a rotation speed of 350 rpm for 1 h to obtain a preform powder, the preform powder is filled into a 316 stainless steel mold with a size of φ20 mm x 6 mm, and the mold is vibrated while the powder is continuously filled, then the filled mold is placed on a powder tablet machine stage, and cold-pressing is performed at a pressure of 150 MPa, with a deformation of 50%, and a Ca3Co4O9 preform with a size of φ20 mm x 3 mm is obtained after demolding;

[0072] Step four, solid-phase sintering: the Ca3Co4O9 preform obtained in step three is placed in a tube furnace for solid-phase sintering, and a stepwise heating method is adopted, i.e., the temperature is raised to 300℃ at a rate of 15℃ / min and kept for 10 min, then the temperature is raised to 800℃ at a rate of 10℃ / min and kept for 10 min, and finally the temperature is raised to 850℃ at a rate of 5℃ / min and kept for 20 h, and then the furnace is cooled to room temperature, and a Ca3Co4O9 thermoelectric catalytic material is obtained.

[0073] Example 7

[0074] This example includes the following steps:

[0075] Step one, raw material powder mixing: CaO powder, Co3O4 powder and Tb4O7 powder with a mass purity of more than 99% are used as raw materials, and the raw materials are weighed according to the stoichiometric ratio of the target product Ca 2.5 Tb 0.5 Co4O9, the weighed raw material powder is poured into an agate ball mill jar and agate milling balls are put in the jar according to a ball-to-powder ratio of 20:1, then argon gas is flushed into the agate ball mill jar and the jar is sealed, and the jar is placed in a planetary ball mill to perform ball milling at a rotation speed of 450 rpm for 2 h to obtain a mixed powder;

[0076] Step two, preparation of Ca 2.5 Tb 0.5Co4O9 base material: the mixed powder obtained in step one is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, using a staged heating method, heated to 300℃ at a rate of 15℃ / min and kept for 10 min, then heated to 700℃ at a rate of 10℃ / min and kept for 10 min, finally heated to 850℃ at a rate of 5℃ / min and kept for 20 h, and then cooled to room temperature with the furnace, the obtained hot sintered material is taken out and manually crushed and ground, reloaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace, using a staged heating method, heated to 700℃ at a rate of 10℃ / min and kept for 10 min, then heated to 850℃ at a rate of 5℃ / min and kept for 20 h, and then cooled to room temperature with the furnace, and the obtained blocky Ca 2.5 Tb 0.5 Co4O9 base material;

[0077] Step three, cold-pressed green body: the blocky Ca 2.5 Tb 0.5 Co4O9 base material is placed in an agate ball mill jar and agate grinding balls are put in according to a ball-to-powder ratio of 20:1, then argon gas protection is flushed into the agate ball mill jar and sealed, and placed in a planetary ball mill for ball milling, the ball milling speed is 350 rpm, and the ball milling time is 1 h, obtaining a preform powder, the preform powder is filled into a 316 stainless steel mold with a size of φ20 mm x 6 mm, and the mold is vibrated while the material is continuously filled, then the filled mold is placed on the powder tablet press machine loading platform, and cold-pressed into a shape under a pressure of 150 MPa, with a deformation of 50%, and after demolding, a Ca 2.5 Tb 0.5 Co4O9 preform;

[0078] Step four, solid phase sintering: the Ca 2.5 Tb 0.5 Co4O9 preform obtained in step three is placed in a tube furnace for solid phase sintering, using a staged heating method, heated to 300℃ at a rate of 15℃ / min and kept for 10 min, then heated to 800℃ at a rate of 10℃ / min and kept for 10 min, finally heated to 850℃ at a rate of 5℃ / min and kept for 20 h, and then cooled to room temperature with the furnace, obtaining a Ca 2.5 Tb 0.5 Co4O9 thermoelectric catalytic material.

[0079] The above is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A type of Ca 3-x Tb x The application of Co4O9 thermoelectric catalytic material in CO2 waste gas treatment is characterized by... The Ca 3- x Tb x The preparation method of Co4O9 thermoelectric catalytic material includes the following steps: Step 1: Raw material mixing: Using CaO powder, Co3O4 powder, and Tb4O7 powder with a purity greater than 99% as raw materials, according to the target product Ca... 3-x Tb x The raw materials were weighed according to the stoichiometric ratio of Co4O9, where 0≤x≤0.

5. The weighed raw material powder was poured into an agate ball mill jar and agate grinding balls were added. Then, argon gas was injected into the agate ball mill jar for protection and it was sealed. The jar was then placed in a planetary ball mill for ball milling to obtain a mixed powder. Step 2: Preparation of Ca by hot sintering method 3-x Tb x Co4O9 base material: The mixed powder obtained in step one is hot-sintered to obtain blocky Ca. 3-x Tb x Co4O9 base material; the hot sintering process is as follows: the mixed powder is loaded into a cylindrical alumina crucible and manually compacted, then placed in a box-type resistance furnace. A staged heating method is used: the temperature is increased to 300℃ at a rate of 15℃ / min and held for 10 min; then increased to 700℃ at a rate of 10℃ / min and held for 10 min; finally, the temperature is increased to 750℃~950℃ at a rate of 5℃ / min and held for 20 h. Afterwards, the furnace is cooled to room temperature. The obtained hot-sintered material is removed, manually crushed and ground, then loaded back into the cylindrical alumina crucible and manually compacted. It is then placed in a box-type resistance furnace and a staged heating method is used: the temperature is increased to 700℃ at a rate of 10℃ / min and held for 10 min; then increased to 750℃~950℃ at a rate of 5℃ / min and held for 20 h. Afterwards, the furnace is cooled to room temperature. The removed material yields blocky Ca. 3-x Tb x Co4O9 base material; Step 3: Cold pressing of the blank: The block-shaped Ca obtained in Step 2... 3-x Tb x Co4O9 preform was placed in an agate ball mill jar and filled with agate grinding balls. Argon gas was then injected into the jar for protection and it was sealed. The jar was then placed in a planetary ball mill for grinding to obtain a preform powder. This preform powder was then filled into a mold and cold-pressed to obtain Ca. 3-x Tb x Co4O9 preform; Step 4: Solid-state sintering and shaping: The Ca obtained in step 3... 3-x Tb x Co4O9 preforms were placed in a tube furnace for solid-state sintering to obtain Ca 3-x Tb x Co4O9 thermoelectric catalytic material; The pressure for cold pressing is 150 MPa; The solid-state sintering process described in step four is as follows: using a staged heating method, the temperature is raised to 300℃ at a rate of 15℃ / min and held for 10min, then raised to 800℃ at a rate of 10℃ / min and held for 10min, and finally raised to 850℃~1000℃ at a rate of 5℃ / min and held for 20h, and then cooled to room temperature with the furnace.

2. A Ca according to claim 1 3-x Tb x The application of Co4O9 thermoelectric catalytic material in CO2 waste gas treatment is characterized by... The ball milling process described in step one uses a ball-to-material ratio of 20:1, a rotation speed of 450 rpm, and a milling time of 2 hours.

3. A Ca according to claim 1 3-x Tb x The application of Co4O9 thermoelectric catalytic material in CO2 waste gas treatment is characterized by... In step three, the ball milling process uses a ball-to-material ratio of 20:1, a rotation speed of 350 rpm, and a milling time of 1 hour.

4. A Ca according to claim 1 3-x Tb x The application of Co4O9 thermoelectric catalytic material in CO2 waste gas treatment is characterized by... In step three, the preform powder is filled into a 316 stainless steel mold with a diameter × height of φ20mm × 6mm in the filling area. During filling, the mold is vibrated while the powder is continuously added. Then, the filled mold is placed on the platform of a powder tablet press for cold pressing, with a deformation of 50%. After demolding, a Ca tablet with dimensions of φ20mm × 3mm is obtained. 3-x Tb x Co4O9 preform.

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