Preparation method of MOF-derived hollow cobalt oxide-loaded manganese oxide catalyst, product and application thereof
阅读说明：本技术 一种mof衍生中空钴氧化物负载氧化锰催化剂的制备方法及其产品和应用 (Preparation method of MOF-derived hollow cobalt oxide-loaded manganese oxide catalyst, 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：本发明公布了一种MOF衍生中空钴氧化物负载氧化锰催化剂的制备方法及其产品和应用,通过向ZIF-67中采用沉积沉淀方式引入少量的锰,进一步通过同时高温还原和焙烧后得到。所述催化剂以MOF衍生的钴氧化物为载体,氧化锰为负载的活性组分,其中钴和锰的金属摩尔比为10：1。锰的加入提高了钴氧化物对于挥发性有机物苯的催化燃烧性能,显示了较好的应用前景。(The invention discloses a preparation method of an MOF-derived hollow cobalt oxide loaded manganese oxide catalyst, and a product and application thereof. The catalyst takes cobalt oxide derived from MOF as a carrier and manganese oxide as a loaded active component, wherein the metal molar ratio of cobalt to manganese is 10: 1. the addition of manganese improves the catalytic combustion performance of the cobalt oxide on volatile organic benzene, and shows good application prospect.)
1. a preparation method of an MOF derived hollow cobalt oxide loaded manganese oxide catalyst is characterized in that a small amount of manganese is introduced into ZIF-67 in a deposition precipitation mode and is further obtained by simultaneous high-temperature reduction and roasting, and comprises the following steps:
(1) according to the molar ratio of cobalt nitrate to 2-methylimidazole being 1: 5-1: 4 respectively weighing cobalt nitrate hexahydrate Co (NO)3)2﹒6H2Dissolving O and 2-methylimidazole in methanol until the molar concentration of cobalt nitrate is 0.03-0.04 mol/L; stirring at room temperature for 12-24 h, centrifuging, collecting precipitate, washing with methanol, and drying at 60 deg.C in a forced air drying oven to obtain ZiF-67;
(2) according to the molar ratio of cobalt to manganese of 10: 1, weighing 50% manganese nitrate solution, and dissolving in deionized water to prepare 0.01-0.02 mol/L manganese nitrate solution;
(3) preparing a sodium hydroxide solution with the concentration of 0.01-0.02 mol/L in stoichiometric proportion to the manganese nitrate;
(4) dispersing the ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2) to obtain a mixed solution;
(5) dropwise adding the solution obtained in the step (3) into the mixed solution obtained in the step (4) under stirring, and continuously stirring for 2-4 h to obtain a suspension;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at 60 ℃ for 12-24 h to obtain a sample;
(7) placing the sample obtained in the step (6) in a tubular furnace, and introducing a hydrogen-argon mixed gas of 5% H2And in the/Ar, roasting for 2h at 800 ℃, switching to air after cooling to room temperature, heating to 500 ℃, and continuing roasting for 2h to obtain the MOF derived cobalt oxide loaded manganese oxide catalyst.
2. The method of making the MOF-derived hollow cobalt oxide supported manganese oxide catalyst of claim 1, prepared by the steps of:
(1) according to the molar ratio of cobalt nitrate to 2-methylimidazole being 1: 5-1: 4 weighing 3.60 g cobalt nitrate hexahydrate Co (NO) respectively3)2﹒6H2O and 3.60 g of 2-methylimidazole are dissolved in 360 mL of methanol; stirring at room temperature for 12h, centrifuging, collecting precipitate, washing with methanol for several times, and drying at 60 deg.C in a forced air drying oven to obtain ZiF-67;
(2) weighing 0.44 g of 50% manganese nitrate solution, and dissolving in 124 mL of deionized water to prepare 0.01mol/L manganese nitrate solution;
(3) weighing 0.10 g of NaOH and dissolving in 247 mL of deionized water to prepare a sodium hydroxide solution with the concentration of 0.01 mol/L;
(4) dispersing the ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2) to obtain a mixed solution;
(5) dropwise adding the sodium hydroxide solution obtained in the step (3) into the mixed solution obtained in the step (4) under stirring, and continuously stirring for 2 hours to obtain a suspension;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at 60 ℃ for 12 hours to obtain a sample;
(7) placing the sample obtained in the step (6) in a tubular furnace, and introducing a hydrogen-argon mixed gas of 5% H2And in the/Ar, roasting for 2h at 800 ℃, switching to air after cooling to room temperature, heating to 500 ℃, and continuing roasting for 2h to obtain the MOF derived cobalt oxide loaded manganese oxide catalyst.
3. The method of making the MOF-derived hollow cobalt oxide supported manganese oxide catalyst of claim 1, prepared by the steps of:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 4.06 g of 2-methylimidazole in 309 mL of methanol, and after stirring 12 at room temperature, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving the solution in 62 mL of deionized water to prepare 0.02 mol/L manganese nitrate solution;
(3) weighing 0.1 g of NaOH and dissolving in 124 mL of deionized water to prepare 0.02 mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 4 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 24 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
4. The method of making the MOF-derived hollow cobalt oxide supported manganese oxide catalyst of claim 1, prepared by the steps of:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 5.08 g of 2-methylimidazole in 412 mL of methanol, and after stirring at room temperature for 12 hours, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving the solution in 62 mL of deionized water to prepare 0.02 mol/L manganese nitrate solution;
(3) weighing 0.1 g of NaOH and dissolving in 124 mL of deionized water to prepare 0.02 mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 2 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 12 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
5. The method of making the MOF-derived hollow cobalt oxide supported manganese oxide catalyst of claim 1, prepared by the steps of:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 5.08 g of 2-methylimidazole in 309 mL of methanol, and after stirring at room temperature for 12 hours, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving in 124 mL of deionized water to prepare 0.01mol/L manganese nitrate solution;
(3) weighing 0.10 g of NaOH and dissolving in 247 mL of deionized water to prepare 0.01mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 2 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 12 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
6. An MOF-derived hollow cobalt oxide supported manganese oxide catalyst, characterized by being prepared by the method of any one of claims 1 to 5, wherein the catalyst is prepared by taking an MOF-derived cobalt oxide as a carrier and manganese oxide as a supported active component, wherein the metal molar ratio of cobalt to manganese is 10: 1.
7. use of an MOF-derived hollow cobalt oxide-supported manganese oxide catalyst according to claim 6 in catalyzing benzene oxidation reactions.
Technical Field
The invention belongs to the technical field of catalytic environmental protection, and particularly relates to a preparation method of an MOF-derived hollow cobalt oxide-loaded manganese oxide catalyst, and a product and application thereof.
Background
Volatile Organic Compounds (VOCs) are one of the main sources of atmospheric pollution, are mostly toxic substances, can cause cancers, and are fine particulate matters (PM 2.5) and ozone (O)3) The important precursor of the compound brings great harm to the health of human bodies. VOCs have the characteristics of wide sources, strong volatility, various types and the like, and the treatment difficulty is high, so that the treatment of VOCs is always a focus and key problem concerned by personnel in the industry. According to the types and characteristics of VOCs, common VOCs treatment methods include adsorption, absorption, membrane separation, condensation, combustion, photocatalytic oxidation, biodegradation, plasma, and the like. The catalytic combustion method is a widely applied green catalytic technology and can thoroughly oxidize VOCs into nontoxic CO2And water, which has the characteristic of no secondary pollution, is receiving more attention.
The catalyst is critical. In addition to noble metals, the study of transition metal oxides has attracted widespread attention. Composite materials composed of binary or ternary metal oxides tend to exhibit superior catalytic performance relative to single metal oxides over single metal oxides. The catalytic performance is improved by the synergistic effect between the binary metals. The invention provides a preparation method of an MOF derived cobalt oxide loaded manganese oxide catalyst, which utilizes the three-dimensional confinement effect of MOFs (metal-organic frameworks) to obtain the cobalt oxide loaded manganese oxide catalyst with a good catalytic effect on benzene catalytic combustion. According to research, the method of the invention has less patents and documents for preparing cobalt oxide supported manganese oxide.
Disclosure of Invention
The invention aims to provide a preparation method of an MOF-derived hollow cobalt oxide-supported manganese oxide catalyst.
Yet another object of the present invention is to: provides a MOF derived hollow cobalt oxide supported manganese oxide catalyst 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 an MOF derived hollow cobalt oxide loaded manganese oxide catalyst is characterized in that a small amount of manganese is introduced into ZIF-67 in a deposition precipitation mode and is further obtained by simultaneous high-temperature reduction and roasting, and comprises the following steps:
(1) weighing cobalt nitrate hexahydrate (Co (NO)3)2﹒6H2O) and 2-methylimidazole are dissolved in methanol, the mixture is stirred for 12 to 24 hours at room temperature, then the precipitate is collected by centrifugation, and the precipitate is dried in a forced air drying oven after being washed by the methanol. Controlling the temperature at 60 ℃ to obtain ZiF-67; wherein the molar ratio of the cobalt nitrate to the 2-methylimidazole is 1: 5-1: 4; the molar concentration of the cobalt nitrate is 0.03-0.04 mol/L;
(2) according to the molar ratio of cobalt to manganese of 10: 1, weighing 50% manganese nitrate solution, and dissolving in deionized water to prepare 0.01-0.02 mol/L manganese nitrate solution;
(3) preparing a sodium hydroxide solution with the concentration of 0.01-0.02 mol/L in stoichiometric proportion to the manganese nitrate;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 2-4 h;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 12-24 h;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
The invention provides an MOF-derived hollow cobalt oxide loaded manganese oxide catalyst which is prepared according to the method, wherein the catalyst takes the MOF-derived cobalt oxide as a carrier and manganese oxide as a loaded active component, wherein the metal molar ratio of cobalt to manganese is 10: 1.
the invention provides an application of an MOF-derived hollow cobalt oxide loaded manganese oxide catalyst in a catalytic benzene oxidation reaction.
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 zinc-based catalyst is obtained by introducing a small amount of manganese into ZIF-67 in a deposition precipitation mode and further performing high-temperature reduction and roasting at the same time. The catalyst takes cobalt oxide derived from MOF as a carrier and manganese oxide as a loaded active component, wherein the metal molar ratio of cobalt to manganese is 10: 1. the obtained cobalt oxide has a hollow structure, and the addition of manganese improves the catalytic combustion performance of the cobalt oxide on volatile organic benzene, and shows a good application prospect.
The invention has the following characteristics:
(1) the material is novel: the hollow cobalt oxide derived from the MOF is used as a carrier to load manganese oxide, and the method has innovation.
(2) The preparation is simple: the cobalt and manganese precursors are reduced and oxidized simultaneously, so that the preparation method is simple and a roasting process is not needed.
Detailed Description
Example 1
An MOF-derived hollow cobalt oxide supported manganese oxide catalyst is prepared by introducing a small amount of manganese into ZIF-67 in a deposition precipitation mode, and further performing high-temperature reduction and roasting at the same time, and comprises the following steps:
(1) according to the molar ratio of cobalt nitrate to 2-methylimidazole being 1: 5-1: 4 weighing 3.60 g cobalt nitrate hexahydrate Co (NO) respectively3)2﹒6H2O and 3.60 g of 2-methylimidazole are dissolved in 360 mL of methanol; stirring at room temperature for 12h, centrifuging, collecting precipitate, washing with methanol for several times, and drying at 60 deg.C in a forced air drying oven to obtain ZiF-67;
(2) weighing 0.44 g of 50% manganese nitrate solution, and dissolving in 124 mL of deionized water to prepare 0.01mol/L manganese nitrate solution;
(3) weighing 0.10 g of NaOH and dissolving in 247 mL of deionized water to prepare a sodium hydroxide solution with the concentration of 0.01 mol/L;
(4) dispersing the ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2) to obtain a mixed solution;
(5) dropwise adding the sodium hydroxide solution obtained in the step (3) into the mixed solution obtained in the step (4) under stirring, and continuously stirring for 2 hours to obtain a suspension;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at 60 ℃ for 12 hours to obtain a sample;
(7) placing the sample obtained in the step (6) in a tubular furnace, and introducing a hydrogen-argon mixed gas of 5% H2And in the/Ar, roasting for 2h at 800 ℃, switching to air after cooling to room temperature, heating to 500 ℃, and continuing roasting for 2h to obtain the MOF derived cobalt oxide loaded manganese oxide catalyst.
The effect of catalytic oxidation of benzene is shown in table 1.
Example 2
An MOF-derived hollow cobalt oxide supported manganese oxide catalyst, similar to the procedure of example 1, was prepared by the following steps:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 4.06 g of 2-methylimidazole in 309 mL of methanol, and after stirring 12 at room temperature, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving the solution in 62 mL of deionized water to prepare 0.02 mol/L manganese nitrate solution;
(3) weighing 0.1 g of NaOH and dissolving in 124 mL of deionized water to prepare 0.02 mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 4 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 24 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
The effect of catalytic oxidation of benzene is shown in table 1.
Example 3
An MOF-derived hollow cobalt oxide supported manganese oxide catalyst, similar to the procedure of example 1, was prepared by the following steps:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 5.08 g of 2-methylimidazole in 412 mL of methanol, and after stirring at room temperature for 12 hours, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving the solution in 62 mL of deionized water to prepare 0.02 mol/L manganese nitrate solution;
(3) weighing 0.1 g of NaOH and dissolving in 124 mL of deionized water to prepare 0.02 mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 2 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 12 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
The effect of catalytic oxidation of benzene is shown in table 1.
Example 4
An MOF-derived hollow cobalt oxide supported manganese oxide catalyst, similar to the procedure of example 1, was prepared by the following steps:
(1) 3.60 g of cobalt nitrate hexahydrate (Co (NO) was weighed3)2﹒6H2O) and 5.08 g of 2-methylimidazole in 309 mL of methanol, and after stirring at room temperature for 12 hours, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Weighing 0.44 g of 50% manganese nitrate solution, and dissolving in 124 mL of deionized water to prepare 0.01mol/L manganese nitrate solution;
(3) weighing 0.10 g of NaOH and dissolving in 247 mL of deionized water to prepare 0.01mol/L sodium hydroxide solution;
(4) dispersing ZIF-67 obtained in the step (1) in the manganese nitrate solution obtained in the step (2);
(5) dropwise adding the solution obtained in the step (3) into the solution obtained in the step (4) under stirring, and continuously stirring for 2 hours;
(6) carrying out suction filtration on the suspension obtained in the step (5), alternately washing the suspension with deionized water and methanol, and drying the suspension in a forced air drying oven at the temperature of 60 ℃ for 12 hours;
(7) placing the sample obtained in step (6) in a tube furnace, and introducing a mixed gas of hydrogen and argon (5% H)2Ar) 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 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide loaded manganese oxide catalyst.
The effect of catalytic oxidation of benzene is 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 in 360 mL of methanol, and after stirring 12 at room temperature, the precipitate was collected by centrifugation and washed several times with methanol, and the precipitate was dried in a forced air drying oven. The temperature was controlled at 60 ℃ to give ZiF-67.
(2) Placing the sample obtained in the step (1) in a tube furnace, and introducing a hydrogen-argon mixed gas (5% H)2Ar) roasting for 2h, and then being roastedThe temperature is 800 ℃, air is switched into after the temperature is reduced to the room temperature, and the temperature is increased to 500 ℃ to continue roasting for 2 hours. Obtaining the MOF derived cobalt oxide catalyst.
The performance of the catalysts obtained in examples 1 to 4 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 with the catalysts prepared in examples 1 to 4 and comparative example 1. Wherein the temperatures (. degree. C.) for the conversion of 10%, 50% and 100%, respectively, T10%、T50%And T100%As can be seen from Table 1, examples 1-4 all have better effects on catalyzing the oxidation of benzene than comparative example 1. This demonstrates that, after the introduction of manganese, the catalytic performance of the MOF derived cobalt oxide supported manganese oxide is improved,
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