阅读说明：本技术 一种高分散负载型钴基催化剂及其制备方法 (High-dispersion supported cobalt-based catalyst and preparation method thereof ) 是由 李雷 于 2019-09-18 设计创作，主要内容包括：本发明属于化工催化技术领域,具体涉及一种高分散负载型钴基催化剂及其制备方法。所述催化剂包括钴和多孔材料,其中,所述多孔材料为载体,所述钴为配体,所述钴负载于多孔材料上,其中,多孔材料为SiO<Sub>2</Sub>、TiO<Sub>2</Sub>、Al<Sub>2</Sub>O<Sub>3</Sub>、ZrO<Sub>2</Sub>或分子筛材料。制备步骤如下：(1)首先,采用等体积浸渍法制备多孔材料负载的钴盐,并将其干燥；(2)将干燥后的样品与一定量的2-甲基咪唑混合、研磨,再进行干燥；(3)将干燥后的样品先后经过惰性气氛和空气进行焙烧,获得高分散负载型氧化钴催化剂。通过这种方法制备的催化剂,具有高分散性、制备方法可重复、所需溶剂量小、可拓展、适合工业化规模放大。(The invention belongs to the technical field of chemical catalysis, and particularly relates to a high-dispersion supported cobalt-based catalyst and a preparation method thereof. The catalyst comprises cobalt and a porous material, wherein the porous material is a carrier, the cobalt is a ligand, the cobalt is loaded on the porous material, and the porous material is SiO 2 、TiO 2 、Al 2 O 3 、ZrO 2 Or a molecular sieve material. The preparation steps are as follows: (1) firstly, preparing a cobalt salt loaded on a porous material by adopting an isometric impregnation method, and drying the cobalt salt; (2) mixing the dried sample with a certain amount of 2-methylimidazole, grinding and drying; (3) and roasting the dried sample in an inert atmosphere and air in sequence to obtain the high-dispersion supported cobalt oxide catalyst. The catalyst prepared by the method has high dispersibility, repeatable preparation method, small required solvent amount, expandable property and suitability for industrial scale amplification.)

1. The high-dispersion supported cobalt-based catalyst is characterized by comprising cobalt and a porous material, wherein the porous material is a carrier, the cobalt is a ligand, the cobalt is supported on the porous material, and the porous material is SiO₂、TiO₂、Al₂O₃、ZrO₂Or a molecular sieve material.

2. A highly dispersed supported cobalt-based catalyst according to claim 2, wherein the cobalt loading is 30 ~ 50% of the support mass.

3. The method for preparing a high-dispersion supported cobalt-based catalyst as claimed in claim 1, comprising the steps of:

(1) dissolving cobalt nitrate serving as a metal salt precursor in water, adding a porous material serving as a carrier by adopting an isometric impregnation method, standing at room temperature for 6-24 hours, and drying to obtain a sample loaded with cobalt salt;

(2) fully mixing the sample loaded with the cobalt salt obtained in the step (1) with 2-methylimidazole, grinding for 5-10 min, and drying to obtain a porous material loaded metal cobalt organic framework material;

(3) and (3) sequentially placing the metal cobalt organic framework material loaded by the porous material obtained in the step (2) in an inert atmosphere and air for roasting to obtain the high-dispersion loaded cobalt-based catalyst.

4. The preparation method of the high-dispersion supported cobalt-based catalyst according to claim 3, wherein the mass ratio of the 2-methylimidazole to the cobalt nitrate is 2-20: 1.

5. The preparation method of the high-dispersion supported cobalt-based catalyst according to claim 3, wherein the drying temperature in the step (1) and the drying temperature in the step (2) are 60-100 ℃, and the drying time is 6-24 h.

6. The method for preparing a high-dispersion supported cobalt-based catalyst as claimed in claim 3, wherein the inert gas in step (3) is nitrogen or argon, and the flow rate is 20-60 mL/min.

7. The preparation method of the high-dispersion supported cobalt-based catalyst according to claim 3, wherein the calcination temperature in the step (3) is 500-700 ℃ and the calcination time is 2-6 h.

Technical Field

The invention belongs to the technical field of chemical catalysis, and particularly relates to a high-dispersion supported cobalt-based catalyst and a preparation method thereof.

Background

The supported catalyst is used as the core of heterogeneous catalysis and is widely applied to the fields of petroleum, coal chemical industry and fine chemical industry. In addition, it is also an indispensable contribution in the field of environmental purification. The preparation method of the supported catalyst mainly comprises an impregnation method, a precipitation method, a sol-gel method, a hydrothermal method and the like. In view of the availability of a catalyst support, the impregnation method is generally one of the most widely used methods for preparing catalysts in industry. It is well known that the performance of a catalyst is closely related to the parameters of the catalyst, such as structure, size, etc. In general, small size particles of the catalyst exhibit excellent catalytic performance. However, the supported catalyst prepared by the impregnation method shows a wide size distribution and serious agglomeration/sintering. Currently, many strategies are used to improve the preparation method, such as controlling the particle size of the catalyst by adjusting the precursor type of the catalyst, controlling the calcination conditions, or using the pre-modification of the carrier. However, these methods also become quite difficult when the catalyst loading is greater than 20%. Thus, preparing high loading, highly dispersed supported catalysts remains a challenge.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a high-dispersion supported cobalt-based catalyst and a preparation method thereof.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a high-dispersion supported cobalt-based catalyst comprises cobalt and a porous material, wherein the porous material is a carrier, the cobalt is a ligand, the cobalt is supported on the porous material, and the porous material is SiO₂、TiO₂、Al₂O₃、ZrO₂Or a molecular sieve material.

Preferably, the loading of the cobalt is SiO₂30-50% of the mass of the carrier.

A preparation method of a high-dispersion supported cobalt-based catalyst comprises the following steps:

(1) dissolving cobalt nitrate serving as a metal salt precursor in water, adding a porous material serving as a carrier by adopting an isometric impregnation method, standing at room temperature for 6-24 hours, and drying to obtain a sample loaded with cobalt salt;

(2) fully mixing the sample loaded with the cobalt salt obtained in the step (1) with 2-methylimidazole, grinding for 5-10 min, and drying to obtain a porous material loaded metal cobalt organic framework material;

(3) and (3) sequentially placing the metal cobalt organic framework material loaded by the porous material obtained in the step (2) in an inert atmosphere and air for roasting to obtain the high-dispersion loaded cobalt-based catalyst.

Preferably, the mass ratio of the 2-methylimidazole to the cobalt nitrate is 2-20: 1.

Preferably, the drying temperature in the step (1) and the step (2) is 60-100 ℃, and the drying time is 6-24 h.

Preferably, the inert gas in the step (3) is nitrogen or argon, and the flow rate is 20-60 mL/min.

Preferably, the roasting temperature in the step (3) is 500-700 ℃, and the roasting time is 2-6 h.

Compared with the prior art, the invention has the following beneficial effects:

(1) compared with the catalyst obtained by traditional impregnation-roasting, the supported cobalt-based catalyst prepared by the method has high dispersion, small-size nano particles and enhanced metal-carrier interaction, and shows better catalytic effect, so that the supported cobalt-based catalyst shows higher catalytic performance in a series of oxidation reactions such as methane catalytic combustion and the like.

(2) The high-dispersion supported cobalt-based catalyst prepared by the method is applied to methane catalytic combustion reaction, and the application field of the material is widened.

(3) The method has the advantages of wide raw material source, simple preparation process, repeatability, capability of expanding other porous material supported catalysts, suitability for industrial large-scale production, and very high application prospect and practical value in the field of catalytic materials.

Drawings

FIG. 1 is a silica-supported cobalt oxide catalyst (CoO) prepared in example 1_x/SiO₂-500 NA);

FIG. 2 is a silica-supported cobalt oxide catalyst (CoO) prepared in example 2_x/SiO₂HRTEM image of 500A).

Detailed Description

The present invention will be described in further detail with reference to the following embodiments. It will be understood by those skilled in the art that the following examples are illustrative of the present invention only and should not be taken as limiting the scope of the invention. The specific techniques or conditions are not indicated in the examples, and the techniques or conditions described in the literature in the art are performed in accordance with the instructions. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available. Example 1

A preparation method of a high-dispersion supported cobalt-based catalyst comprises the following steps:

(1) 0.55g of cobalt nitrate salt was weighed out and dissolved in 100g of deionized water, and 10.0g of SiO was added₂And (4) standing the aerosol for 12h, and drying the aerosol in an oven at 70 ℃ for 12h to obtain a silicon dioxide supported cobalt salt sample.

(2) 2.5g of 2-methylimidazole is weighed, mixed with the sample obtained in step (1), ground for 5min and then placed in an oven at 70 ℃ for drying for 12 h.

(3) Placing the bluish purple solid sample obtained in the step (2) in a tubular furnace to be roasted for 2h at 500 ℃ under the atmosphere of nitrogen (40 mL/min), and then placing the bluish purple solid sample in the atmosphere of air at 500 ℃ to be kept for 2h to obtain a final product, namely CoO_x/SiO₂-500NA, said CoO_x/SiO₂The-500 NA electron micrograph is shown in figure 1, and the loading amount of the catalyst is up to 30% of the weight of the carrier.