阅读说明：本技术 一种等级孔大孔-介孔γ-Al2O3催化剂载体材料及其制备方法 (Hierarchical porous macroporous-mesoporous gamma-Al2O3Catalyst carrier material and preparation method thereof ) 是由 陈丽华 雷坤皓 张净铭 侯月新 刘思明 孙晓芳 钟运开 苏宝连 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种具有等级孔大孔-介孔γ-Al_2O_3催化剂载体材料及其制备方法。该γ-Al_2O_3催化剂载体材料具有大孔和介孔孔道,大孔孔壁由氧化铝纳米片组装而成,纳米片间相互堆积成褶皱状并形成丰富的介孔孔道,且大孔与介孔交叉贯通,比表面积高,反应活性位点多,反应所需能垒低,催化性能好。本发明通过一步制备生成具有等级孔大孔-介孔体系的催化剂载体材料,该方法反应条件温和,操作简便,杂质引入量极少,有利于工业化推广。(The invention discloses a macroporous-mesoporous gamma-Al with hierarchical pores 2 O 3 A catalyst carrier material and a preparation method thereof. The gamma-Al 2 O 3 The catalyst carrier material is provided with macropores and mesoporous channels, the walls of the macropores are assembled by alumina nano sheets, the nano sheets are mutually stacked into a corrugated shape to form rich mesoporous channels, and the macropores and the mesopores are crossed and communicated, so that the specific surface area is high, the number of reaction active sites is large, the energy barrier required by the reaction is low, and the catalytic performance is good. The invention generates the macropores with hierarchical pores by one-step preparationThe method has the advantages of mild reaction conditions, simple and convenient operation, very small impurity introduction amount and contribution to industrial popularization.)

1. Macroporous-mesoporous gamma-Al with hierarchical pores₂O₃Catalyst support material, characterized in that the gamma-Al is₂O₃The catalyst carrier material is a massive solid with a macroporous-mesoporous structure of high connectivity grade pores, the walls of the macroporous pores are assembled by alumina nano sheets, the nano sheets are mutually stacked into a corrugated shape to form rich mesoporous channels, and the macropores are in cross communication with the mesopores.

2. The macroporous-mesoporous γ -Al with hierarchical pores of claim 1₂O₃Catalyst support material, characterized in that the gamma-Al is₂O₃In the catalyst carrier material, the aperture of the macropore is 500nm-1 μm; the mesoporous aperture is 5-10 nm.

3. The macroporous-mesoporous γ -Al with hierarchical pores of claim 1₂O₃Catalyst support material, characterized in thatγ-Al₂O₃In the catalyst carrier material, the length of the alumina nanosheet is 80-100nm, the width is 40-60nm, and the thickness is 10-20 nm.

4. The macroporous-mesoporous gamma-Al of any one of claims 1 to 3 having hierarchical pores₂O₃The preparation method of the catalyst carrier material is characterized by comprising the following steps:

1) mixing methanol and deionized water, and stirring to obtain a clear solution;

2) dropwise adding aluminum sec-butoxide into the clear solution prepared in the step 1) to obtain a mixed solution;

3) standing the mixed solution obtained in the step 2), performing suction filtration, and drying to obtain a white precipitate precursor;

4) firing the white precipitate precursor obtained in the step 3) to obtain the macroporous-mesoporous gamma-Al with hierarchical pores₂O₃A catalyst support material.

5. The method according to claim 4, wherein the molar ratio of the aluminum sec-butoxide to the methanol is 1 (0.05-50).

6. The production method according to claim 5, wherein the molar ratio of the aluminum sec-butoxide to the methanol is 1: (15-45).

7. The method according to claim 4, wherein the volume ratio of the methanol to the deionized water is (1:19) - (19: 1).

8. The method according to claim 7, wherein the volume ratio of the methanol to the deionized water is (1:3) - (3: 1).

9. The method according to claim 4, wherein the reaction of step 2) is carried out at 25 to 60 ℃.

10. The method according to claim 4, wherein the stirring time in the step 1) is 5 to 10 min; the standing time in the step 3) is 30-60 min; the drying temperature in the step 3) is 40-60 ℃, and the drying time is 24-48 h; the burning temperature in the step 4) is 500-550 ℃, and the burning time is 2-3 h.

Technical Field

The invention relates to gamma-Al₂O₃The technical field of catalyst carrier materials, in particular to a hierarchical porous-mesoporous gamma-Al₂O₃A catalyst carrier material and a preparation method thereof.

Background

In the current industrial production, support materials that have been put into practical use include alumina, activated carbon, titanium oxide, aluminosilicate, and the like. Among them, alumina carriers having excellent properties are most widely used, and account for about 70% or more of industrial supported catalyst carriers. Among the numerous crystalline phases of alumina, gamma-Al₂O₃The performance is optimal. Because of the advantages of adjustable pore canal property, large specific surface area, strong adsorbability, adjustable surface acidity and alkalinity, large mechanical strength, high thermal stability and the like, the gamma-Al alloy has the characteristics of high strength, high thermal stability and the like₂O₃Also known as "activated alumina".

The pore channel property is not only an important index for evaluating the performance of the catalyst, but also an important factor influencing the catalytic performance, and mainly relates to a series of structural parameters such as specific surface area, pore volume, average pore diameter, pore size distribution and the like of the material. The higher specific surface area can effectively increase the contact area of reactants and the catalyst, and simultaneously ensure the uniform distribution of active components. The introduction of the pore system further increases the flow diffusivity of reactants, and can effectively improve the problems of catalyst blockage, carbon deposition and the like. However, in the current industrial preparation method, under the condition of no additional template agent or surfactant, the alumina carrier material with high specific surface area and excellent pore canal property is difficult to prepare, which is also a main problem that the overall catalytic efficiency of the catalyst is difficult to further improve. Even if the template agent or the surfactant is introduced, the large-scale production and application of the template agent are limited by factors of complex preparation, high operation requirement, high price of the surfactant and the like. Therefore, the development of the alumina carrier material with high specific surface area and low cost and high efficiency can be realized, the pore channel property of the alumina carrier material can be effectively improved and regulated, more choices are provided for catalytic reaction, and the method is a great problem which is commonly concerned by researchers at present.

Disclosure of Invention

The invention aims to provide a hierarchical porous macroporous-mesoporous gamma-Al₂O₃The catalyst carrier material has a hierarchical pore macroporous-mesoporous structure, the wall of a macroporous hole is formed by stacking and assembling alumina nano sheets with mesoporous channels, the specific surface area is high, the catalytic performance is good, the preparation condition is mild, the operation is simple, the impurities are less, and the catalyst carrier material is suitable for industrial production.

In order to achieve the purpose, the invention adopts the technical scheme that:

macroporous-mesoporous gamma-Al with hierarchical pores₂O₃Catalyst support material, the gamma-Al₂O₃The catalyst carrier material is a massive solid with a macroporous-mesoporous structure of high connectivity grade pores, the walls of the macroporous pores are assembled by alumina nano sheets, the nano sheets are mutually stacked into a corrugated shape to form rich mesoporous channels, and the macropores are in cross communication with the mesopores.

According to the above scheme, gamma-Al₂O₃In the catalyst carrier material, the aperture of the macropore is 500nm-1 μm; the mesoporous aperture is 5-10 nm.

According to the above scheme, gamma-Al₂O₃In the catalyst carrier material, the length of the alumina nanosheet is 80-100nm, the width is 40-60nm, and the thickness is 10-20 nm.

The macroporous-mesoporous gamma-Al with hierarchical pores₂O₃A method for preparing a catalyst support material comprising the steps of:

1) mixing methanol and deionized water, and stirring to obtain a clear solution;

2) dropwise adding aluminum sec-butoxide into the clear solution prepared in the step 1) to obtain a mixed solution;

3) standing the mixed solution obtained in the step 2), performing suction filtration, and drying to obtain a white precipitate precursor;

4) firing the white precipitate precursor obtained in the step 3) to obtain the macroporous-mesoporous gamma-Al with hierarchical pores₂O₃A catalyst support material.

According to the scheme, the molar ratio of the aluminum sec-butoxide to the methanol is 1 (0.05-50), preferably 1: (15-45).

According to the scheme, the volume ratio of the methanol to the deionized water is (1:19) - (19:1), and preferably (1:3) - (3: 1).

According to the scheme, the stirring time in the step 1) is 5-10 min.

According to the above scheme, the reaction of step 2) is carried out at 25-60 ℃.

According to the scheme, the standing time in the step 3) is 30-60 min.

According to the scheme, the drying temperature in the step 3) is 40-60 ℃, and the drying time is 24-48 h.

According to the scheme, the ignition temperature in the step 4) is 500-550 ℃, and the ignition time is 2-3 h.

The invention utilizes the spontaneous hydrolysis condensation of the metal organic alcohol ester in water, alcohol molecules generated by hydrolysis are gathered and diffused outwards, so that a pore channel is formed in the material, and the rapid synthesis of the hierarchical pore macroporous-mesoporous metal oxide material with different pore diameters can be realized by one-step method by adjusting and controlling the hydrolysis condensation reaction speed of the metal organic alcohol ester. The polar solvent methanol adopted by the invention is a protic solvent, and is easy to generate hydrogen bonds with nucleophilic reagent water, so that the nucleophilic reagent water is solvated, a solvated solution system has a certain catalytic action on the hydrolysis reaction of organic alcohol ester, the hydrolysis product aluminum hydroxide hydrate is promoted to grow along a two-dimensional crystal face, nano sheets are finally formed and stacked into a corrugated shape to generate mesopores, and the nano sheets are assembled to form the wall of a macropore. The two-dimensional nanosheets have highly exposed surfaces and edges, which can provide opportunities for developing high-performance catalysts, generally speaking, catalytic reactions are easy to occur at defects such as steps, corners and sections of materials, the nanosheets are easy to form defects due to structural distortion, energy barriers required by the defects during catalytic reactions are much lower, and the highly exposed surfaces provide high specific surface areas and are beneficial to loading of active sites.

The invention has the beneficial effects that:

1. the invention provides the macroporous-mesoporous gamma-Al with hierarchical pores₂O₃The wall of a macroporous hole of the catalyst carrier material is assembled by alumina nano sheets, the nano sheets are mutually stacked into a wrinkle shape to form rich mesoporous channels, and the macropores are communicated with the mesopores in a crossing way, so that the catalyst carrier material has the advantages of high specific surface area, more reactive active sites, low energy barrier required by reaction and good catalytic performance.

2. According to the method, the catalyst carrier material with a hierarchical pore macroporous-mesoporous system is generated in one step by utilizing the hydrolytic condensation reaction of the organic aluminum alkoxide in the protonic polar solution methanol, and the nanosheet structure of the hydrolysate growing along the two-dimensional crystal face is also beneficial to the loading of active sites and the catalytic reaction in the later period.

Drawings

FIG. 1 is a graph of graded pore γ -Al produced in examples 1 and 2 of the present invention₂O₃Wide angle diffraction XRD pattern of catalyst support material.

FIG. 2 is a view showing the graded pore gamma-Al obtained in example 1 of the present invention₂O₃Scanning electron micrographs of the catalyst support material, where panels a and b are at different magnifications.

FIG. 3 is a view showing the graded pore γ -Al obtained in example 2 of the present invention₂O₃Scanning electron micrographs of the catalyst support material.

FIG. 4 is a view showing the graded pore γ -Al produced in example 3 of the present invention₂O₃Scanning electron micrographs of the catalyst support material.

FIG. 5 is a graph of graded pore γ -Al produced in examples 1 and 2 of the present invention₂O₃Nitrogen adsorption curve of catalyst support material.

FIG. 6 is a view showing the graded pore γ -Al produced in example 3 of the present invention₂O₃Nitrogen adsorption curve of catalyst support material.

Detailed Description

The present invention will be further described with reference to the following drawings and examples, but the present invention is not limited to the following examples.

In the following examples, all the reagents are commercially available chemical reagents unless otherwise specified.