Preparation method of manganese-modified carbon nanotube-loaded cobalt oxide, product and application thereof
阅读说明：本技术 一种锰改性的碳纳米管负载钴氧化物的制备方法及其产品和应用 (Preparation method of manganese-modified carbon nanotube-loaded cobalt oxide, product and application thereof ) 是由 崔大祥 袁静 蔡婷 赵昆峰 童琴 于 2020-12-17 设计创作，主要内容包括：本发明公开了一种锰改性的碳纳米管负载钴氧化物的制备方法及其产品和应用,通过表面活性剂CTAB调控制备金属元素锰掺杂的双金属MOF材料CoMn-MOF,并以此为牺牲模板,经高温还原性气氛下碳化后空气气氛下焙烧得到。限制硝酸钴和硝酸锰的摩尔比为(10～35)：1,硝酸钴和CTAB的摩尔比为(73～75)：1,硝酸钴和2-甲基咪唑的摩尔比为1：50～3：100,硝酸钴和硝酸锰的总金属摩尔浓度为0.05～0.08 mol/L,2-甲基咪唑的摩尔浓度为0.60～0.70 mol/L。金属有机框架促使钴和锰在高温处理下不团聚,对苯催化燃烧的催化性能表现出极好的催化性能。(The invention discloses a preparation method of manganese modified carbon nanotube loaded cobalt oxide, a product and application thereof. Limiting the molar ratio of the cobalt nitrate to the manganese nitrate to (10-35): 1, the molar ratio of cobalt nitrate to CTAB is (73-75): 1, the molar ratio of cobalt nitrate to 2-methylimidazole is 1: 50-3: 100, the total metal molar concentration of cobalt nitrate and manganese nitrate is 0.05-0.08 mol/L, and the molar concentration of 2-methylimidazole is 0.60-0.70 mol/L. The metal organic framework promotes the cobalt and the manganese not to agglomerate under high-temperature treatment, and shows excellent catalytic performance on catalytic combustion of benzene.)
1. a preparation method of manganese modified carbon nanotube loaded cobalt oxide is characterized in that a surfactant CTAB is used for regulating and controlling to prepare a metal element manganese-doped bimetallic MOF material CoMn-MOF, the metal element manganese-doped bimetallic MOF material CoMn-MOF is used as a sacrificial template, and the sacrificial template is obtained by carbonization in a high-temperature reducing atmosphere and roasting in an air atmosphere, and comprises the following steps:
(1) cobalt nitrate hexahydrate Co (NO) is weighed3)2﹒6H2Dissolving O, 50% manganese nitrate aqueous solution and Cetyl Trimethyl Ammonium Bromide (CTAB) in deionized water, wherein the molar ratio of cobalt nitrate to manganese nitrate is (10-35): 1, the molar ratio of cobalt nitrate to CTAB is (73-75): 1, the total metal molar concentration of cobalt nitrate and manganese nitrate is 0.05-0.08 mol/L; weighing 2-methylimidazole, and dissolving in deionized water, wherein the molar concentration of the 2-methylimidazole is 0.60-0.70 mol/L; mixing the two solutions, wherein the molar ratio of cobalt nitrate to 2-methylimidazole is 1: 50-3: stirring at room temperature for 1-2 h, standing and aging for 24 h; the precipitate was collected by centrifugation, washed with ethanol and dried in a forced air drying oven. Controlling the temperature to be 80 ℃ to obtain ZiF-67 modified by manganese;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 h at 800 ℃, switching to air after cooling to room temperature, heating to 300 ℃, and continuing roasting for 2 h to obtain the manganese modified carbon nano tube loaded cobalt oxide.
2. The preparation method of the manganese-modified carbon nanotube-supported cobalt oxide according to claim 1, characterized by comprising the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate Co (NO) was weighed out3)2﹒6H2O, 0.07 g of 50% aqueous manganese nitrate solution and 0.01g of CTAB (cetyltrimethylammonium bromide) were dissolved in 44 mL of deionized water; weighing 8.21 g of 2-methylimidazole and dissolving in 167 mL of deionized water; mixing the two solutionsMixing, stirring at room temperature for 1-2 h, standing and aging for 24 h; centrifuging, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 h at 800 ℃, switching to air after cooling to room temperature, heating to 300 ℃, and continuing roasting for 2 h to obtain the manganese modified carbon nano tube loaded cobalt oxide.
3. The preparation method of the manganese-modified carbon nanotube-supported cobalt oxide according to claim 1, characterized by comprising the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O), 0.036 g of 50% aqueous manganese nitrate solution and 0.01g of cetyltrimethylammonium bromide (CTAB) were dissolved in 35 mL of deionized water; weighing 8.21 g of 2-methylimidazole and dissolving in 167 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing, aging for 24h, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, the air is switched after the temperature is reduced to the room temperature, and the temperature is increased to 300 ℃ to continue roasting for 2 hours. Obtaining the manganese modified carbon nano tube loaded cobalt oxide.
4. The preparation method of the manganese-modified carbon nanotube-supported cobalt oxide according to claim 1, characterized by comprising the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O), 0.024 g of 50% aqueous manganese nitrate solution and 0.01g of cetyltrimethylammonium bromide (CTAB) were dissolved in 30 mL of deionized water; weighing 8.21 g of 2-methylimidazole, and dissolving in 143 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h. Centrifuging to collect precipitate, washing with ethanol, and drying in air-blast drying oven 80Drying at the temperature of DEG C to obtain ZiF-67 modified by manganese;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, switching to air after the temperature is reduced to room temperature, and heating to 300 ℃ to continue roasting for 2 hours until the manganese modified carbon nano tube loads cobalt oxide.
5. The preparation method of the manganese-modified carbon nanotube-supported cobalt oxide according to claim 1, characterized by comprising the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O), 0.02 g of 50% aqueous manganese nitrate solution and 0.01g of cetyltrimethylammonium bromide (CTAB) were dissolved in 26 mL of deionized water; weighing 8.21 g of 2-methylimidazole, and dissolving in 143 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h. Centrifuging, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, switching to air after the temperature is reduced to room temperature, and heating to 300 ℃ to continue roasting for 2 hours until the manganese modified carbon nano tube loads cobalt oxide.
6. Manganese-modified carbon nanotube-supported cobalt oxide, characterized in that it is prepared according to the method of any one of claims 1 to 5.
7. Use of the manganese-modified carbon nanotube-supported cobalt oxide of claim 6 in the catalytic combustion reaction of benzene.
Technical Field
The invention belongs to the technical field of catalytic environmental protection, and particularly relates to a preparation method of manganese-modified carbon nanotube-loaded cobalt oxide, and a product and application thereof.
Background
Metal organic framework compounds (MOFs) are porous materials with a repeating network structure synthesized by self-assembly of metal ions or metal cluster compound ions and organic ligands. MOFs have abundant and changeable structures, and show excellent application prospects in the fields of gas adsorption, separation, catalysis, sensing and the like in recent years. The large porosity and specific surface area of the MOFs and the repeated periodic structure are beneficial to the uniform distribution of MOFs active sites, and the MOFs have larger application potential in the field of catalysis.
In recent years, MOF-derived porous nanomaterials have received much attention because they retain the unique structure of MOFs. For example, inorganic carbon materials with good conductivity can be obtained by roasting, and the inorganic carbon materials are applied to the fields of electrocatalysis, supercapacitors, batteries and the like, or metal oxides, metal sulfides, metal phosphides, metal carbides and the like are obtained by roasting with MOFs as precursors and are applied to the fields of catalysis, sensors and the like. In general, the most common oxides derived from MOFs are single metal oxides, binary or ternary metal oxide composites are often used in electrocatalytic applications, such as NiCo2O4、ZnFe2O4/ZnO, etc. The application of the method in the thermal catalytic oxidation reaction in the field of environmental catalysis generally requires high-temperature air atmosphere treatment, and the uniformity of product distribution is difficult to ensure. The final composition and structural morphology of the MOFs are directly influenced by the synthesis method, the raw material ratio and the like.
Disclosure of Invention
The invention provides a preparation method of manganese modified carbon nanotube loaded cobalt oxide.
Yet another object of the present invention is to: provides a manganese modified carbon nano tube loaded cobalt oxide product prepared by the method.
Yet another object of the present invention is to: provides an application of the product.
The purpose of the invention is realized by the following scheme: a preparation method of manganese modified carbon nanotube loaded cobalt oxide is characterized in that a bimetallic MOF material CoMn-MOF doped with manganese metal element is prepared by regulating and controlling a surfactant CTAB, and is taken as a sacrificial template, carbonized in a high-temperature reducing atmosphere and then roasted in an air atmosphere, and the preparation method comprises the following steps:
(1) weighing cobalt nitrate hexahydrate (Co (NO)3)2﹒6H2O), 50% manganese nitrate aqueous solution and cetyltrimethylammonium bromide (CTAB) were dissolved in deionized water; weighing 2-methylimidazole and dissolving in deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h. The precipitate was collected by centrifugation, washed with ethanol and dried in a forced air drying oven. Controlling the temperature to be 80 ℃ to obtain ZiF-67 modified by manganese;
wherein the molar ratio of the cobalt nitrate to the manganese nitrate is 10: 1-35: 1, the molar ratio of cobalt nitrate to CTAB is 73: 1-75: 1, the molar ratio of cobalt nitrate to 2-methylimidazole is 1: 50-3: 100, the total metal molar concentration of cobalt nitrate and manganese nitrate is 0.05-0.08 mol/L, and the molar ratio of 2-methylimidazole is 0.60-0.70 mol/L;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, the air is switched after the temperature is reduced to the room temperature, and the temperature is increased to 300 ℃ to continue roasting for 2 hours. Obtaining the manganese modified carbon nano tube loaded cobalt oxide.
The invention provides a manganese-modified carbon nanotube-loaded cobalt oxide prepared by the method.
The invention provides application of manganese modified carbon nano tube loaded cobalt oxide in catalytic combustion reaction of benzene.
The performance of the catalysts obtained in the examples in the catalytic oxidation of benzene: the catalyst is put in a continuous flow fixed bed device and mixed gas of benzene and air is introduced for reaction; the reaction pressure is normal pressure to 1 atm, the total gas flow is 50 mL/min, the reaction space velocity is 30000 mL/(g.h), and the initial concentration of benzene in the mixed gas is 1000 ppm.
The metal organic framework promotes cobalt and manganese not to agglomerate under high-temperature treatment, and the metal organic framework is applied to the catalytic combustion reaction of benzene and shows excellent catalytic performance.
The invention has the following characteristics:
(1) the preparation is simple and the material is novel: the manganese-modified carbon nanotube-supported cobalt catalyst is directly obtained from bimetallic CoMn-MOF, and the material is novel and the preparation method is simple.
(2) The performance is excellent: the modification of manganese improves the catalytic combustion performance of cobalt oxide on benzene.
Detailed Description
Example 1
A manganese-modified carbon nanotube-loaded cobalt oxide is prepared by preparing a bimetallic MOF material CoMn-MOF doped with a manganese metal element through regulation and control of a surfactant CTAB, taking the obtained bimetallic MOF material CoMn-MOF as a sacrificial template, carbonizing the sacrificial template in a high-temperature reducing atmosphere, and roasting the carbonized bimetallic MOF material in an air atmosphere, and is prepared by the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate Co (NO) was weighed out3)2﹒6H2O, 0.07 g of 50% aqueous manganese nitrate solution and 0.01g of CTAB (cetyltrimethylammonium bromide) were dissolved in 44 mL of deionized water; weighing 8.21 g of 2-methylimidazole and dissolving in 167 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h; centrifuging, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 h at 800 ℃, switching to air after cooling to room temperature, heating to 300 ℃, and continuing roasting for 2 h to obtain the manganese modified carbon nano tube loaded cobalt oxide.
The results of the catalytic oxidation of benzene by the product catalyst of this example are shown in Table 1.
Example 2
The manganese modified carbon nanotube supported cobalt oxide is similar to the step of the embodiment 1, and is prepared by the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O）、0036 g of 50% aqueous manganese nitrate solution and 0.01g of cetyltrimethylammonium bromide (CTAB) were dissolved in 35 mL of deionized water; weighing 8.21 g of 2-methylimidazole and dissolving in 167 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing, aging for 24h, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, the air is switched after the temperature is reduced to the room temperature, and the temperature is increased to 300 ℃ to continue roasting for 2 hours. Obtaining the manganese modified carbon nano tube loaded cobalt oxide.
The results of the catalytic oxidation of benzene by the product catalyst of this example are shown in Table 1.
Example 3
The manganese modified carbon nanotube supported cobalt oxide is similar to the step of the embodiment 1, and is prepared by the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O), 0.024 g of 50% aqueous manganese nitrate solution and 0.01g of cetyltrimethylammonium bromide (CTAB) were dissolved in 30 mL of deionized water; weighing 8.21 g of 2-methylimidazole, and dissolving in 143 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h. Centrifuging, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, switching to air after the temperature is reduced to room temperature, and heating to 300 ℃ to continue roasting for 2 hours until the manganese modified carbon nano tube loads cobalt oxide.
The results of the catalytic oxidation of benzene by the product catalyst of this example are shown in Table 1.
Example 4
The manganese modified carbon nanotube supported cobalt oxide is similar to the step of the embodiment 1, and is prepared by the following steps:
(1) 0.58 g of cobalt nitrate hexahydrate (Co (NO) was weighed out3)2﹒6H2O), 0.02 g of 50% nitreManganese acid aqueous solution and 0.01g Cetyl Trimethyl Ammonium Bromide (CTAB) dissolved in 26 mL deionized water; weighing 8.21 g of 2-methylimidazole, and dissolving in 143 mL of deionized water; mixing the two solutions, stirring at room temperature for 1-2 h, standing and aging for 24 h. Centrifuging, collecting precipitate, washing with ethanol, and drying the precipitate in a forced air drying oven at 80 deg.C to obtain manganese-modified ZiF-67;
(2) the manganese-modified ZiF-67 was placed in a tube furnace and a hydrogen-argon mixture (5% H) was passed through2and/Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, switching to air after the temperature is reduced to room temperature, and heating to 300 ℃ to continue roasting for 2 hours until the manganese modified carbon nano tube loads cobalt oxide.
The results of the catalytic oxidation of benzene by the product catalyst of this example are shown in Table 1.
Comparative example 1:
preparation of MOF-derived cobalt oxide:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 4.74 g of 2-methylimidazole are dissolved in 360 mL of methanol, the mixture is stirred at room temperature for 12 hours, then the precipitate is collected by centrifugation and washed by methanol for a plurality of times, and the precipitate is dried in a forced air drying oven at 60 ℃ to obtain ZiF-67;
(2) placing the sample obtained in the step (1) in a tube furnace, and introducing a hydrogen-argon mixed gas (5% H)2and/Ar) roasting for 2 hours, wherein the roasting temperature is 800 ℃, switching to air after the temperature is reduced to room temperature, and heating to 500 ℃ to continue roasting for 2 hours to obtain the MOF derived cobalt oxide catalyst.
The performance of the catalysts obtained in examples 1 to 4 and comparative example 1 in the catalytic oxidation of benzene: the catalyst is put in a continuous flow fixed bed device and mixed gas of benzene and air is introduced for reaction; the reaction pressure is normal pressure to 1 atm, the total gas flow is 50 mL/min, the reaction space velocity is 30000 mL/(g.h), and the initial concentration of benzene in the mixed gas is 1000 ppm.
Table 1 shows the results of catalytic oxidation of benzene by the catalysts prepared in examples 1 to 4 and comparative example 1, wherein the temperatures T are 10%, 50% and 100% conversion, respectively10%、T50%And T100%As can be seen from Table 1, the benzene oxidation reactions catalyzed by examples 1-4 are all superior to those catalyzed by comparative example 1:
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