Normal-temperature manganese composite catalyst, preparation method and application

Abstract

The invention discloses a normal-temperature manganese composite catalyst, a preparation method and application, and mainly relates to the technical field of manganese-containing catalysts. Compared with the prior art, the normal-temperature manganese composite catalyst disclosed by the invention realizes efficient broad-spectrum catalytic decomposition of toxic and harmful gases through the synergistic effect of manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerous nitrate and cobalt acetate metal salts; phosphoric acid modified vanadium dioxide and titanium nitride are compounded to serve as a catalyst carrier, the thermal stability and the specific surface area of the catalyst are enhanced, dispersity of metal active components on the catalyst carrier is further optimized through loading of nickel acetylacetonate, firm combination of the active components and the carrier is guaranteed through high-temperature calcination, and the catalytic activity of the catalyst is improved. The prepared catalyst has a high specific surface area and an optimized pore structure, can catalytically decompose various gaseous pollutants at normal temperature, better realizes an air purification effect, and remarkably improves the air purification effect.

Description

Technical Field

[0001] The invention relates to the technical field of manganese-containing catalysts, and in particular to a room-temperature manganese composite catalyst, a preparation method and an application thereof. Background Art

[0002] Manganese catalysts are metal catalysts containing manganese, which can be widely used in environmental governance, chemical synthesis and energy conversion. In terms of air purification, manganese catalysts can catalyze the decomposition of toxic and harmful gases into harmless carbon dioxide and water, mainly including common indoor formaldehyde, ammonia, benzene, toluene and other volatile organic compounds (VOCs). These substances usually come from decoration materials, furniture and daily chemicals. They can be harmlessly treated through air purification, thereby improving indoor air quality and protecting people's respiratory health. The role of the catalyst carrier is to increase the specific surface area of ​​the catalyst and provide more active sites, thereby improving the dispersion and contact efficiency of the catalyst, ensuring the efficient catalytic reaction, and can also enhance the mechanical strength and stability of the catalyst and extend the service life of the catalyst.

[0003] Commonly used manganese-based catalyst carriers include silicon dioxide, titanium dioxide, carbon nanotubes, metal oxides, etc.; composite carrier materials can also be formed by doping metals into the carrier. Common metal doping elements include but are not limited to palladium, platinum, nickel, copper, iron and cobalt, which can synergistically enhance chemical activity, adjust pore structure and specific surface area, promote the transfer of electrons from the catalyst carrier to active sites, accelerate the catalytic reaction rate, and provide additional active sites to enhance the adsorption capacity of the catalyst, which helps to improve the selectivity and efficiency of the catalytic reaction and better achieve air purification effects.

[0004] Chinese invention patent application CN104289238A discloses a catalyst for degrading ozone at room temperature, its preparation method and application, which is mainly CePO4 modified with one or more oxides of manganese, iron and cobalt. The components used in the invention are cheap and easy to obtain. The prepared catalyst has good O3 degradation activity at room temperature, and the O3 removal rate at room temperature can reach more than 98%. When used for a long time, its O3 degradation activity can still reach more than 95%, and it is suitable for the degradation of low-concentration ozone. The preparation method of the catalyst is also disclosed. After CePO4 is prepared by the sol-gel method, the salts of manganese, iron and cobalt are mixed and impregnated, and the finished product is obtained by calcination after drying; the preparation method is simple and suitable for industrial production. The application of the catalyst in an air purifier is also disclosed, which solves the technical problem that the air purifier with photocatalysis and plasma as the core technology in the prior art does not involve the degradation of the ozone generated by itself.

[0005] Chinese invention patent application CN104725021A discloses a room temperature catalytic oxidation air purification decorative material and its preparation method, using gypsum powder and lime powder as adhesives, activated zeolite powder adsorbent, and nano silver / copper / iron / manganese composite oxide as catalysts. The decorative material of the invention contains a nano silver / copper / iron / manganese composite oxide catalyst, so that the air purification decorative material has the function of adsorbing and decomposing harmful substances at room temperature above 14°C, especially the oxidation and decomposition effect of carbon monoxide and formaldehyde is obvious.

[0006] The composite catalyst of the above invention patent can remove harmful gases such as formaldehyde and carbon monoxide at room temperature, but cannot widely remove a variety of toxic and harmful gases. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to catalytically decompose a variety of gaseous pollutants at room temperature to achieve a better air purification effect.

[0008] To achieve the above-mentioned purpose, the present invention provides a room-temperature manganese composite catalyst, a preparation method and an application thereof.

[0009] The preparation method of the room temperature manganese composite catalyst comprises the following steps:

[0010] (1) Weighing vanadium dioxide and adding it to water, ultrasonically dispersing it for 0.5-1 hour, adding a phosphoric acid aqueous solution, stirring for 3-5 hours, concentrating and drying at 80-100° C., grinding, and calcining in a muffle furnace at 300-500° C. for 1-2 hours to obtain modified vanadium dioxide, which is set aside;

[0011] (2) adding titanium nitride and modified vanadium dioxide to anhydrous ethanol, mixing at 140-180 r / min for 20-24 hours, drying at 50-60° C., physically mixing by a ball mill, wherein the grinding beads are zirconium oxide balls, grinding to obtain a catalyst carrier for standby use;

[0012] (3) dissolving nickel acetylacetonate in benzene to obtain an impregnation solution, dispersing by ultrasonication for 0.5-1 hour, adding the catalyst support to impregnate for 6-8 hours, drying at 50-60° C., grinding, and calcining at 200-220° C. for 1-2 hours to obtain a nickel-supported catalyst support for later use;

[0013] (4) weighing manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate and cobalt acetate, adding them to water, stirring at room temperature for 1-2 hours, adding a nickel-supported catalyst carrier and impregnating for 6-10 hours, drying at 80-100° C., drying at 100-120° C. for 1 hour, grinding, and calcining in a muffle furnace at 400-600° C. for 4-6 hours to obtain the room temperature manganese composite catalyst.

[0014] In the step (1), the weight ratio of vanadium dioxide, water and phosphoric acid aqueous solution is 30-50:300-500:30-50.

[0015] The phosphoric acid aqueous solution in step (1) is a 5-10 wt % phosphoric acid aqueous solution.

[0016] In the step (2), the weight ratio of titanium nitride, modified vanadium dioxide and anhydrous ethanol is 60-70:30-50:400-600.

[0017] In the step (3), the weight ratio of nickel acetylacetonate, benzene and catalyst carrier is 0.5-2:10-20:100-110.

[0018] In the step (4), the weight ratio of manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate, cobalt acetate and water is 2-5: 0.5-2: 0.5-2: 0.1-0.4: 0.4-0.6: 0.4-0.6: 100-120.

[0019] The application of the room temperature manganese composite catalyst is characterized in that it can be applied to an air purifier.

[0020] Manganese nitrate is used as the main manganese source in the catalyst, and decomposes to produce MnOx species in the catalyst. These species can effectively capture gaseous pollutants and decompose them, and decompose gaseous pollutants such as formaldehyde and benzene into carbon dioxide and water, and the recycling ensures the continuity and efficiency of the catalytic reaction, and improves the activity and stability of the catalyst. Manganese carbonate is dispersed on the catalyst carrier to form highly dispersed active sites, which not only increases the specific surface area of ​​the catalyst, but also provides more adsorption and reaction opportunities for gaseous pollutants, and the carbon dioxide produced by the decomposition of manganese carbonate can also be discharged as a by-product of the reaction in some cases, without causing secondary pollution. The application of manganese acetate in the catalyst can provide a mild manganese source, and in the catalytic reaction, the coordination of acetate may help to stabilize a specific manganese oxide form, and the acidic environment generated during the decomposition process may help to optimize the surface acidity of the catalyst, reduce the adsorption and activation of pollutants. Ferric nitrate is introduced into the composite catalyst of the present invention with iron element, and the iron transition metal can promote the activation and dissociation of oxygen, free up more active sites to adsorb gaseous pollutants, and help to improve the long-term performance of the catalyst. The rare earth ions in cerium nitrate have variable valence characteristics, which can easily achieve the transition between trivalent and tetravalent, and can react with hydroxyl radicals. This conversion is accompanied by adsorption and release, which increases the catalyst's storage and adsorption capacity for gaseous pollutants, thereby improving the purification efficiency of indoor air pollutants. The introduction of cobalt acetate in the catalyst enhances the redox ability of cobalt in the application, helps to improve the electronic conductivity of the catalyst, promotes the activation of pollutant molecules, and increases the rate of catalytic reaction. Manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate, cobalt acetate and other metal salts play a synergistic role in the catalyst to jointly improve the catalytic performance. The ready-made composite catalyst has higher catalytic activity and stability, which helps to improve the overall performance of the room temperature manganese composite catalyst in the air purifier, achieve catalytic efficiency, and catalytically decompose a variety of gaseous pollutants.

[0021] The present invention uses phosphoric acid-modified vanadium dioxide and titanium nitride as catalyst carriers, and obtains a more uniform fine particle size through physical mixing in a ball mill, which helps to improve the specific surface area of ​​the catalyst and the contact efficiency of the reactants. Titanium nitride, as a high-strength, high-hardness inorganic material, provides good stability and mechanical strength, and can withstand the high temperature and pressure conditions of subsequent processing; the porous structure of titanium nitride increases the specific surface area and optimizes the pore structure, thereby improving the transfer efficiency of reactants and products; the high electronic conductivity of titanium nitride helps to accelerate the electron transfer process in the catalytic reaction. The introduction of modified vanadium dioxide brings more active sites and optimized pore structure to the catalyst carrier, increases the specific surface area, and thus improves the efficiency of the catalytic reaction. The process of physical mixing in a ball mill not only helps to achieve uniform dispersion of the two materials, but also promotes the interface bonding between them through mechanical force, thereby enhancing the overall performance of the carrier. Through the synergistic effect of the composite carrier, the catalyst exhibits higher activity, better selectivity and better stability when catalytically decomposing a variety of gaseous pollutants. The present invention also adds nickel acetylacetonate to load the catalyst carrier, which can provide uniformly dispersed nickel active sites on the catalyst carrier, provide additional electron transfer channels, and promote the redox reaction; the nickel loading also optimizes the pore structure of the catalyst carrier, increases its specific surface area, thereby increasing the contact opportunity with gaseous pollutants and improving the catalytic efficiency.

[0022] Beneficial effects of the present invention:

[0023] The room-temperature manganese composite catalytic material of the present invention has the performance of efficient and broad-spectrum catalytic decomposition of toxic and harmful gases, and the catalytic performance is jointly improved by the synergistic effect of metal salts such as manganese nitrate, manganese carbonate, manganese acetate, iron nitrate, cerium nitrate, and cobalt acetate in the catalyst, and the ready-made composite catalyst has higher catalytic activity and stability, which is helpful to improve the overall performance of the room-temperature manganese composite catalyst in the air purifier, realize catalytic synergy, and catalytic decomposition of various gaseous pollutants. Phosphoric acid-modified vanadium dioxide and titanium nitride are composited as catalyst carriers, and finally these metal salt active components are impregnated on the acetylacetone nickel-loaded catalyst carrier, which not only realizes the uniform dispersion of various metal active components, but also realizes the firm combination between these components and the carrier through high-temperature calcination, thereby preparing a room-temperature manganese composite catalyst with high specific surface area, optimized pore structure and enhanced catalytic activity, so that it can efficiently catalyze the decomposition of various gaseous pollutants at room temperature, and realize a significant improvement in air purification effect. DETAILED DESCRIPTION

[0024] The parameters of the specific chemical substances used in the examples are from the following sources:

[0025] Vanadium dioxide: particle size is 1 μm, purity is 99.9wt%, manufacturer is Qinghe County Chaotai Metal Materials Co., Ltd., product number is LF-VO2-W001.

[0026] Titanium nitride: purity is 99.9wt%, average particle size is 40nm, specific surface area w is 92m 2 / g, volume density is 0.12g / cm 3 The manufacturer is Zhejiang Yamei Nano Technology Co., Ltd. and the product number is AM-TiN-072-1.

[0027] Nickel acetylacetonate: The manufacturer is Wuhan Yuancheng Gongchuang Technology Co., Ltd., and the product number is yc2023.

[0028] Example 1

[0029] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0030] (1) Weigh 40 g of vanadium dioxide and add it to 400 g of water, disperse it by ultrasonic at 25 kHz for 0.5 hour, add 40 g of 8 wt % phosphoric acid aqueous solution, stir for 4 hours, concentrate and dry at 90° C., grind to a particle size of 0.04 mm, and calcine in a muffle furnace at 400° C. for 2 hours to obtain modified vanadium dioxide, which is set aside;

[0031] (2) Add 65 g of titanium nitride and 40 g of modified vanadium dioxide to 500 g of anhydrous ethanol, mix at 160 r / min for 24 hours, dry at 60° C., and physically mix by a ball mill, wherein the grinding beads are zirconium oxide balls and the grinding particle size is 0.04 mm, to obtain a catalyst carrier for standby use;

[0032] (3) 1 g of nickel acetylacetonate was dissolved in 20 g of benzene to obtain an impregnation solution, and ultrasonic dispersion was performed at 25 kHz for 0.5 hours. 100 g of the catalyst support was added and impregnated for 8 hours, and then dried at 60° C. The ground particles were ground to a particle size of 0.04 mm, and calcined at 200° C. for 1.5 hours to obtain a nickel-supported catalyst support for later use;

[0033] (4) Weigh 4 g of manganese nitrate, 1 g of manganese carbonate, 1 g of manganese acetate, 0.2 g of ferric nitrate, 0.6 g of cerium nitrate, and 0.4 g of cobalt acetate and add them to 100 g of water. Stir at room temperature for 1 hour, add 100 g of nickel-supported catalyst support and soak for 8 hours, dry at 90° C., and dry at 110° C. for 1 hour. Grind to a particle size of 0.06 mm, and calcine at 500° C. in a muffle furnace for 5 hours to obtain the room-temperature manganese composite catalyst.

[0034] Example 2

[0035] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0036] (1) Weigh 40 g of vanadium dioxide and add it to 400 g of water, disperse it by ultrasonic at 25 kHz for 0.5 hour, add 40 g of 8 wt % phosphoric acid aqueous solution, stir for 4 hours, concentrate and dry at 90° C., grind to a particle size of 0.04 mm, and calcine in a muffle furnace at 400° C. for 2 hours to obtain modified vanadium dioxide, which is set aside;

[0037] (2) Add 65 g of titanium nitride and 40 g of modified vanadium dioxide to 500 g of anhydrous ethanol, mix at 160 r / min for 24 hours, dry at 60° C., and physically mix by a ball mill, wherein the grinding beads are zirconium oxide balls and the grinding particle size is 0.04 mm, to obtain a catalyst carrier for standby use;

[0038] (3) Weigh 4 g of manganese nitrate, 1 g of manganese carbonate, 1 g of manganese acetate, 0.2 g of ferric nitrate, 0.6 g of cerium nitrate, and 0.4 g of cobalt acetate and add them to 100 g of water. Stir at room temperature for 1 hour, add 100 g of catalyst carrier and soak for 8 hours, dry at 90° C., and dry at 110° C. for 1 hour. Grind to a particle size of 0.06 mm and calcine at 500° C. in a muffle furnace for 5 hours to obtain the room temperature manganese composite catalyst.

[0039] Example 3

[0040] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0041] (1) Weigh 110 g of vanadium dioxide and add it to 1100 g of water, disperse it by ultrasonic at 25 kHz for 0.5 hour, add 110 g of 8 wt % phosphoric acid aqueous solution, stir for 4 hours, concentrate and dry at 90° C., grind to a particle size of 0.04 mm, and calcine in a muffle furnace at 400° C. for 2 hours to obtain modified vanadium dioxide, which is set aside;

[0042] (2) dissolving 1 g of nickel acetylacetonate in 20 g of benzene to obtain an impregnation solution, dispersing the solution by ultrasonication at 25 kHz for 0.5 h, adding 100 g of modified vanadium dioxide and impregnating the solution for 8 h, drying the solution at 60° C., grinding the solution to a particle size of 0.04 mm, and calcining the solution at 200° C. for 1.5 h to obtain a nickel-supported catalyst carrier for later use;

[0043] (3) Weigh 4 g of manganese nitrate, 1 g of manganese carbonate, 1 g of manganese acetate, 0.2 g of ferric nitrate, 0.6 g of cerium nitrate, and 0.4 g of cobalt acetate and add them to 100 g of water. Stir at room temperature for 1 hour, add 100 g of nickel-supported catalyst support and soak for 8 hours, dry at 90° C., and dry at 110° C. for 1 hour. Grind to a particle size of 0.06 mm, and calcine at 500° C. in a muffle furnace for 5 hours to obtain the room-temperature manganese composite catalyst.

[0044] Example 4

[0045] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0046] (1) dissolving 1 g of nickel acetylacetonate in 20 g of benzene to obtain an impregnation solution, dispersing the solution by ultrasonication at 25 kHz for 0.5 h, adding 100 g of titanium nitride and impregnating the solution for 8 h, drying the solution at 60° C., grinding the solution to a particle size of 0.04 mm, and calcining the solution at 200° C. for 1.5 h to obtain a nickel-supported catalyst carrier for later use;

[0047] (2) Weigh 4 g of manganese nitrate, 1 g of manganese carbonate, 1 g of manganese acetate, 0.2 g of ferric nitrate, 0.6 g of cerium nitrate, and 0.4 g of cobalt acetate and add them to 100 g of water. Stir at room temperature for 1 hour, add 100 g of nickel-supported catalyst support and soak for 8 hours, dry at 90° C., and dry at 110° C. for 1 hour. Grind to a particle size of 0.06 mm and calcine at 500° C. in a muffle furnace for 5 hours to obtain the room-temperature manganese composite catalyst.

[0048] Comparative Example 1

[0049] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0050] (1) Weigh 110 g of vanadium dioxide and add it to 1100 g of water, disperse it by ultrasonic at 25 kHz for 0.5 hour, add 110 g of 8 wt % phosphoric acid aqueous solution, stir for 4 hours, concentrate and dry at 90° C., grind to a particle size of 0.04 mm, and calcine in a muffle furnace at 400° C. for 2 hours to obtain modified vanadium dioxide, which is set aside;

[0051] (2) Weigh 4 g of manganese nitrate, 1 g of manganese carbonate, 1 g of manganese acetate, 0.2 g of ferric nitrate, 0.6 g of cerium nitrate, and 0.4 g of cobalt acetate and add them to 100 g of water, stir at room temperature for 1 hour, add 100 g of modified vanadium dioxide and soak for 8 hours, dry at 90° C., and dry at 110° C. for 1 hour. Grind to a particle size of 0.06 mm, and calcine at 500° C. in a muffle furnace for 5 hours to obtain the room temperature manganese composite catalyst.

[0052] Comparative Example 2

[0053] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0054] Weigh 4g of manganese nitrate, 1g of manganese carbonate, 1g of manganese acetate, 0.2g of ferric nitrate, 0.6g of cerium nitrate, and 0.4g of cobalt acetate, add them to 100g of water, stir at room temperature for 1 hour, add 100g of vanadium dioxide and soak for 8 hours, dry at 90°C, and dry at 110°C for 1 hour. The ground particles have a particle size of 0.06mm and are calcined in a muffle furnace at 500°C for 5 hours to obtain the room temperature manganese composite catalyst.

[0055] Comparative Example 3

[0056] A method for preparing a room temperature manganese composite catalyst comprises the following steps:

[0057] Weigh 4g of manganese nitrate, 1g of manganese carbonate, 1g of manganese acetate, 0.2g of ferric nitrate, 0.6g of cerium nitrate, and 0.4g of cobalt acetate, add them to 100g of water, stir at room temperature for 1 hour, add 100g of titanium nitride and soak for 8 hours, dry at 90°C, and dry at 110°C for 1 hour. The ground particles have a particle size of 0.06mm and are calcined at 500°C in a muffle furnace for 5 hours to obtain the room temperature manganese composite catalyst.

[0058] Test Example 1

[0059] The room temperature manganese composite catalyst obtained by the preparation method of Examples 1-4 and Comparative Examples 1-3 was applied to an air purifier for air quality test. In a closed indoor space containing benzene, ammonia, ozone and formaldehyde gas, the air purifier containing the room temperature manganese composite catalyst was used normally for 1 hour. The test refers to the national standard GB / T 18883-2022 "Indoor Air Quality Standard", and the unit of measurement is mg / m 3 The difference in benzene, ammonia, ozone and formaldehyde gas concentrations before and after use was used to determine the decomposition and removal rate of benzene, ammonia, ozone and formaldehyde gases by the air purifier containing the room temperature manganese composite catalyst. The calculation formula is: (gas concentration after use - gas concentration before use) × 100%, as summarized in Table 1.

[0060] Table 1 Harmful gas removal rate

[0061] benzene ammonia ozone formaldehyde Example 1 85.6％ 88.8％ 86.5％ 90.0％ Example 2 80.4％ 83.7％ 82.0％ 81.8％ Example 3 81.6％ 83.8％ 82.5％ 82.7％ Example 4 82.5％ 84.0％ 82.7％ 84.4％ Comparative Example 1 70.6％ 72.3％ 73.0％ 74.1％ Comparative Example 2 72.1％ 73.0％ 74.3％ 75.5％ Comparative Example 3 75.0％ 76.3％ 76.9％ 78.6％

[0062] In Example 1, raw material components of manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate, and cobalt acetate are impregnated on a nickel-loaded catalyst carrier. In the preparation of the nickel-loaded catalyst carrier, phosphoric acid-modified vanadium dioxide and titanium nitride are first compounded and used, and then nickel acetylacetonate is added for loading; Example 2 uses a compound of vanadium dioxide and titanium nitride as a catalyst carrier, Example 3 uses nickel-loaded modified vanadium dioxide as a catalyst carrier, and Example 4 uses a compound of nickel-loaded titanium nitride as a catalyst carrier. Comparative Examples 1-3 use modified vanadium dioxide, vanadium dioxide, and titanium nitride as catalyst carriers, respectively. By comparison, it can be seen that the catalytic decomposition rate of Example 1 for benzene, ammonia, ozone, and formaldehyde gas is higher than that of other examples and comparative examples. Among them, titanium nitride itself has a high specific surface area, which can provide more attachment points and reaction sites for active components, thereby increasing the contact opportunities between the catalyst and the reactants and improving the rate of the catalytic reaction. The active sites provided by vanadium dioxide for the catalyst help increase the contact area between the reactants and the catalyst and improve the catalytic efficiency. Phosphoric acid-modified vanadium dioxide enhances the thermal stability of vanadium dioxide by introducing phosphate ions, so that it maintains a stable structure during high-temperature calcination and is not easily decomposed. The compounding of phosphoric acid-modified vanadium dioxide and titanium nitride provides more active sites and optimized pore structure for the catalyst, which helps to increase the specific surface area and pore distribution of the catalyst, thereby increasing the effectiveness of the catalytic reaction; the loading of nickel acetylacetonate introduces nickel active metal as a synergistic effect. Nickel, as a transition metal, has high chemical activity and catalytic ability, and can promote the redox reaction. The introduction of nickel provides more catalytic active sites, thereby improving the efficiency of the catalytic reaction. The loading of nickel may also form a metal-carrier interaction with the carrier material. This interaction can optimize the surface electronic state of the catalyst and improve the dispersibility and stability of the catalyst. Therefore, the loading of nickel acetylacetonate effectively improves the broad-spectrum selectivity of the catalyst, achieves catalytic synergy, and catalytically decomposes a variety of gaseous pollutants.

[0063] Test Example 2

[0064] When a room-temperature manganese composite catalyst is used in an air purifier, the larger the specific surface area, the better the adsorption effect, and the better the technical effect of catalytic decomposition of toxic and harmful gases can be achieved. Test Example 2 The room-temperature manganese composite catalyst obtained by the preparation method of Examples 1-4 and Comparative Examples 1-3 was tested. The adsorbent was a room-temperature manganese composite catalyst, the adsorbate was nitrogen, and the nitrogen concentration was 99.99%. The test referred to the national standard GB / T 13390-2008 "Nitrogen adsorption method for the determination of the specific surface area of ​​metal powders". This national standard is applicable to the determination of the specific surface area of ​​metal powders, and can also be used as a reference for the determination of the specific surface area of ​​non-metallic powders and microporous materials; the measured specific surface area is the total specific surface area of ​​the powder, including the specific surface area of ​​any open pores where nitrogen molecules can enter the powder body. When the adsorbent is placed in a nitrogen system, physical adsorption will occur on its surface at low temperatures; when the adsorption reaches equilibrium, the equilibrium adsorption pressure and the volume of gas adsorbed on the surface of the substance are measured to calculate the adsorption amount V of the sample monolayer m The specific surface area of ​​the sample is calculated and summarized in Table 2.

[0065] Table 2 Specific surface area

[0066] Specific surface area Example 1 <![CDATA[168.4m 2 / g]]> Example 2 <![CDATA[160.2m 2 / g]]> Example 3 <![CDATA[155.0m 2 / g]]> Example 4 <![CDATA[153.7m 2 / g]]>

[0067] In Example 1, a nickel-loaded catalyst carrier is obtained by using a compound of vanadium dioxide modified by phosphoric acid and titanium nitride, and loading nickel acetylacetonate, and then manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate, and cobalt acetate raw material components are impregnated on the nickel-loaded catalyst carrier, which increases the active sites and promotes the increase of specific surface area; Example 2 reduces the nickel loading in the catalyst carrier, limits the further development of the pore structure and the increase of active sites, and the reduction of active sites affects the specific surface area; In Example 3, the phosphoric acid modification of vanadium dioxide produces a large number of acid sites on the catalyst surface, but does not affect the catalyst Redox ability; in Example 3 and Example 4, only one substance is added as a basic catalyst carrier, and then nickel acetylacetonate is loaded, and the specific surface area is lower than that in Example 1; in Example 4, only titanium nitride is added as a catalyst carrier. Titanium nitride itself has a high specific surface area, which can provide more attachment points and reaction sites for the active components, thereby increasing the contact opportunities between the catalyst and the reactants and improving the catalytic efficiency. By using it in combination with phosphoric acid-modified vanadium dioxide, the pore structure and surface properties of titanium nitride can be further optimized, and the specific surface area can be maximized, which is an ideal carrier material for catalyst preparation.

[0068] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a room temperature manganese composite catalyst, characterized in that: The following steps are involved: (1) Weighing vanadium dioxide and adding it to water, ultrasonically dispersing it for 0.5-1 hour, adding a phosphoric acid aqueous solution, stirring for 3-5 hours, concentrating and drying at 80-100° C., grinding, and calcining in a muffle furnace at 300-500° C. for 1-2 hours to obtain modified vanadium dioxide, which is set aside; (2) adding titanium nitride and modified vanadium dioxide to anhydrous ethanol, mixing at 140-180 r / min for 20-24 hours, drying at 50-60° C., physically mixing by a ball mill, wherein the grinding beads are zirconium oxide balls, grinding to obtain a catalyst carrier for standby use; (3) dissolving nickel acetylacetonate in benzene to obtain an impregnation solution, dispersing by ultrasonication for 0.5-1 hour, adding the catalyst support to impregnate for 6-8 hours, drying at 50-60° C., grinding, and calcining at 200-220° C. for 1-2 hours to obtain a nickel-supported catalyst support for later use; (4) weighing manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate and cobalt acetate, adding them to water, stirring at room temperature for 1-2 hours, adding a nickel-supported catalyst carrier and impregnating for 6-10 hours, drying at 80-100° C., drying at 100-120° C. for 1 hour, grinding, and calcining in a muffle furnace at 400-600° C. for 4-6 hours to obtain the room temperature manganese composite catalyst.

2. The method for preparing the room temperature manganese composite catalyst according to claim 1, characterized in that: In the step (1), the weight ratio of vanadium dioxide, water and phosphoric acid aqueous solution is 30-50:300-500:30-50.

3. The method for preparing the room temperature manganese composite catalyst according to claim 1, characterized in that: The phosphoric acid aqueous solution in step (1) is a 5-10 wt % phosphoric acid aqueous solution.

4. The method for preparing the room temperature manganese composite catalyst according to claim 1, characterized in that: In the step (2), the weight ratio of titanium nitride, modified vanadium dioxide and anhydrous ethanol is 60-70:30-50:400-600.

5. The method for preparing the room temperature manganese composite catalyst according to claim 1, characterized in that: In the step (3), the weight ratio of nickel acetylacetonate, benzene and catalyst carrier is 0.5-2:10-20:100-110.

6. The method for preparing the room temperature manganese composite catalyst according to claim 1, characterized in that: In the step (4), the weight ratio of manganese nitrate, manganese carbonate, manganese acetate, ferric nitrate, cerium nitrate, cobalt acetate and water is 2-5: 0.5-2: 0.5-2: 0.1-0.4: 0.4-0.6: 0.4-0.6: 100-120.

7. A room temperature manganese composite catalyst, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

8. An application of the room temperature manganese composite catalyst as claimed in claim 7, characterized in that: Can be used in air purifiers.