CN-122006770-A - Catalyst carrier, preparation method and application thereof

CN122006770ACN 122006770 ACN122006770 ACN 122006770ACN-122006770-A

Abstract

The application relates to a catalyst carrier, a preparation method and application thereof. The catalyst carrier provided by the application comprises active carbon and a nitrogen-doped carbon layer coating the active carbon, wherein the content of nitrogen element in the catalyst carrier is 3% -15% through XPS test. When the catalyst containing the catalyst carrier is applied to hydrofining of crude terephthalic acid, the catalyst has the characteristics of high catalyst activity and long service life.

Inventors

MING ZHENG
GAO XIAOCHEN
ZHU QINGCAI
HE LIMIN
LI XINHUI

Assignees

中国石油化工股份有限公司
中石化（上海）石油化工研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (12)

1. A catalyst carrier comprising activated carbon and a nitrogen-doped carbon layer coating the activated carbon, wherein the content of nitrogen element in the catalyst carrier is 3% -15% by XPS test.
2. The catalyst carrier according to claim 1, wherein the nitrogen content is 5 to 12%, and/or The nitrogen-doped carbon layer comprises a nitrogen-doped hollow carbon nanostructure, preferably a nitrogen-doped hollow carbon nanosphere and/or a nitrogen-doped carbon nanotube; Preferably, the nitrogen-doped carbon layer has an average thickness of 10nm to 1000nm, preferably 100nm to 500nm; Preferably, the nitrogen-doped hollow carbon nanostructure is a nitrogen-doped hollow carbon nanosphere having a particle size of 20nm to 500nm, preferably 50nm to 100nm, and/or The activated carbon is selected from one or more of coal-based carbon, wood-based carbon and shell-based carbon, and/or The activated carbon has a specific surface area of 800m 2 /g-1600m 2 /g, preferably 1000m 2 /g-1300m 2 /g, and/or The pore volume of the activated carbon is 0.30mL/g-0.80mL/g.
3. A method of preparing a catalyst support comprising the steps of: S1, performing a first reaction on silicon dioxide and amino silane in a first solvent to obtain amino silicon dioxide; S2, mixing the amino silicon dioxide and the activated carbon in the step S1 in a second solvent to obtain the activated carbon connected with the amino silicon dioxide; s3, coating the polymer on the activated carbon connected with the amino silicon dioxide in the step S2 to obtain the activated carbon coated with the polymer layer; S4, sequentially pre-oxidizing and carbonizing the activated carbon coated with the polymer layer in the step S3 to obtain the treated activated carbon; And S5, removing silicon dioxide in the activated carbon treated in the step S4 to obtain the catalyst carrier.
4. A process according to claim 3, wherein in step S1, the silica is selected from silica microspheres, preferably having a particle size of 50nm to 500nm, preferably 100nm to 200nm, and/or The amino silane is selected from one or more of compounds shown in a formula I, In formula I, R 1 、R 2 and R 3 are the same or different and are each independently selected from hydrogen and C1-C6 alkyl, and at least one of R 1 、R 2 and R 3 is not hydrogen, preferably selected from C1-C4 alkyl, and L is selected from C1-C6 alkylene, preferably C1-C4 alkylene; Preferably, the amino silane is selected from one or more of 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl tripropoxysilane, 2-aminoethyl trimethoxysilane, 2-aminoethyl triethoxysilane, and 2-aminoethyl tripropoxysilane, and/or The first solvent is selected from C1-C4 monohydric alcohols, preferably from methanol and/or ethanol, and/or The mass ratio of the silicon dioxide to the amino silane is (0.1-1): 1, preferably (0.3-0.7): 1, and/or The temperature of the first reaction is 50-80 ℃, and the time of the first reaction is 1-15 h.
5. The method according to claim 3 or 4, wherein in step S2, the activated carbon is one or more selected from the group consisting of coal-based carbon, wood-based carbon and shell-based carbon, Preferably, the specific surface area of the activated carbon is 800m 2 /g-1600m 2 /g, preferably 1000m 2 /g-1300m 2 /g, preferably the pore volume of the activated carbon is 0.30mL/g to 0.80mL/g, and/or The second solvent is selected from water and/or C1-C4 monohydric alcohol, preferably one or more selected from water, methanol and ethanol, and/or The mass ratio of the aminated silica to the activated carbon is (0.02-2): 1, preferably (0.04-1): 1, and/or The temperature of mixing is 50-80 ℃ and the time of mixing is 1-15 h.
6. The method according to any one of claims 3 to 5, wherein in step S3 The polymer comprises a first polymer and a second polymer, wherein the first polymer is selected from one or more of polyvinyl alcohol, graphene oxide and polyethylene glycol, the second polymer is selected from one or more of polydopamine, polyacrylamide and polylysine, and/or Preferably, the coating polymer comprises: s31, enabling the activated carbon connected with the amination silicon dioxide in the step S2 to react with a first polymer solution to obtain activated carbon coated by a first polymer; S32, reacting the activated carbon coated by the first polymer in the step S31 with a second polymer solution; Optionally, step S33, repeating steps S31 and S32 at least once.
7. The process according to claim 6, wherein in step S31, the first polymer solution is selected from the group consisting of aqueous solutions of the first polymer, preferably the mass ratio of the activated carbon to which the aminated silica is attached to the first polymer is 10 to 150, preferably 40 to 100, and/or In step S31, the reaction temperature is 50-150 ℃ and the reaction time is 1-10 h, and/or In step S32, the second polymer solution is selected from an aqueous solution of a second polymer, preferably the pH of the second polymer solution is 8.0-9.5, preferably the mass ratio of the first polymer coated activated carbon to the second polymer is 10-150, preferably 40-100, and/or In the step S32, the reaction temperature is 10-50 ℃ and the reaction time is 20-60 h.
8. The process according to claim 3 to 7, wherein in step S4, the pre-oxidation is carried out at a temperature of 200℃to 400℃for a period of 1h to 15h, and/or The carbonization treatment is carried out at a temperature of 800-1000 ℃ for a time of 1-15 h, and/or The carbonization treatment being carried out in an inert atmosphere, and/or In step S5, the activated carbon treated in S4 is mixed with an acid solution, preferably selected from hydrofluoric acid solution, to remove silica.
9. The method of any one of claims 3 to 8, wherein the catalyst support comprises activated carbon and a nitrogen-doped carbon layer coating the activated carbon, wherein the content of nitrogen element in the catalyst support is 3% -15% by XPS test; Preferably, the nitrogen element content is 5% -12%, and/or The nitrogen-doped carbon layer comprises a nitrogen-doped hollow carbon nanostructure, preferably a nitrogen-doped hollow carbon nanosphere and/or a nitrogen-doped carbon nanotube; Preferably, the nitrogen-doped carbon layer has an average thickness of 100nm to 500nm; Preferably, the nitrogen doped hollow carbon nanostructure is a nitrogen doped hollow carbon nanosphere having a particle size of 20nm to 500nm, preferably 50nm to 100nm.
10. Use of a catalyst support according to claim 1 or 2 or a catalyst support prepared by a method of preparation according to any one of claims 3 to 9 in the preparation of a hydrogenation catalyst, in particular a crude terephthalic acid hydrogenation catalyst.
11. A crude terephthalic acid hydrogenation catalyst comprising the catalyst support of claim 1 or 2 or the catalyst support prepared by the preparation method of any one of claims 3 to 9 and an active component, Preferably, the active component is selected from one or more of the noble metals, preferably from palladium and/or rhodium; preferably, the mass content of the active component is 0.1% to 1.0%, preferably 0.3% to 0.9%, based on the mass of the catalyst support; preferably, the dispersity of the active component in the crude terephthalic acid hydrogenation catalyst is 20% to 50%, preferably 25% to 40%.
12. A process for producing a crude terephthalic acid hydrogenation catalyst, which comprises impregnating and reducing the catalyst support according to claim 1 or 2 or the catalyst support produced by the production process according to any one of claims 3 to 9 with a source of an active component; Preferably, the active ingredient source is selected from a soluble salt solution of a noble metal, preferably one or more selected from a palladium sulfate solution, a palladium chloride acid solution, a palladium phosphate solution and a potassium tetrachloropalladate solution; preferably, the impregnation is an isovolumetric impregnation; Preferably, the temperature of the reduction is 100-300 ℃ and the time of the reduction is 1-30 h.

Description

Catalyst carrier, preparation method and application thereof Technical Field The application belongs to the field of catalysts, and particularly relates to a catalyst carrier, and a preparation method and application thereof. Background In the hydrofining process of Crude Terephthalic Acid (CTA), impurity benzaldehyde (4-CBA) in CTA generates p-methylbenzoic acid (PT acid) under the catalysis of palladium-carbon, so that the p-methylbenzoic acid (PT acid) is separated from Terephthalic Acid (TA). The 4-CBA is limited by diffusion, and mainly participates in the reaction on the surface layer of the catalyst, and meanwhile, the smaller the size of palladium crystal grains is, the higher the dispersity is, and the higher the catalytic activity is, so that the dispersity of the palladium crystal grains in the palladium-carbon catalyst and the distribution on the surface layer of the activated carbon are main factors influencing the catalytic activity. The hydrofining of crude terephthalic acid is a high-temperature reducing atmosphere, and palladium grains are easy to sinter and grow up under the high-temperature reducing atmosphere, so that the catalytic activity is reduced, which is the most important factor for the deactivation of the industrial palladium-carbon catalyst. In order to improve the stability of the activity of the catalyst, the dispersity of palladium crystal grains is greatly improved, and meanwhile, the physical barrier among the palladium crystal grains is realized, so that the method is an effective way for solving the problems of uneven distribution of palladium, easy sintering of the palladium crystal grains and low activity in the prior art. Disclosure of Invention Aiming at the problems of low activity caused by uneven palladium distribution and short service life caused by easy sintering of palladium grains in the prior art, the application provides a catalyst carrier and a preparation method and application thereof. When the catalyst containing the catalyst carrier is applied to hydrofining of crude terephthalic acid, the catalyst has the characteristics of high catalyst activity and long service life. In a first aspect, the application provides a catalyst carrier, which comprises active carbon and a nitrogen-doped carbon layer coating the active carbon, wherein the content of nitrogen element in the catalyst carrier is 3% -15% through XPS test. In some embodiments, the nitrogen element is present in an amount of 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 14% or any value therebetween. In some embodiments, the nitrogen element is present in an amount of 5% to 12%. In the application, the content of nitrogen element refers to the atomic percentage of nitrogen element in three elements of carbon, nitrogen and oxygen, wherein the atomic percentage is about 4nm of the surface layer of the carrier measured by XPS. In some embodiments, the nitrogen-doped carbon layer comprises nitrogen-doped hollow carbon nanostructures. In some embodiments, are nitrogen-doped hollow carbon nanospheres and/or nitrogen-doped carbon nanotubes. According to the catalyst carrier provided by the application, a uniform nitrogen-doped nano cavity structure is introduced into the surface layer of the active carbon, so that on one hand, the dispersion degree of active crystal grains can be improved, the physical separation among active component crystal grains is realized, and on the other hand, the bonding strength of palladium and the carrier can be increased due to the proper nitrogen doping content, the sintering resistance is further improved, active sites can be shielded due to the fact that the nitrogen content is too high, the exposed active sites of the palladium are reduced, and the dispersion degree is reduced. The catalyst containing the catalyst carrier has the characteristics of high catalyst activity and long sintering-resistant service life. In some embodiments, the nitrogen-doped carbon layer has an average thickness of 10nm to 1000nm, such as 50nm、100nm、150nm、200nm、250nm、300nm、350nm、400nm、450nm、500nm、550nm、600nm、650nm、700nm、750nm、800nm、850nm、800nm、950nm or any value therebetween. In some embodiments, the nitrogen-doped carbon layer has an average thickness of 100nm to 500nm. When the average thickness of the nitrogen-doped carbon layer is too high, the corresponding nitrogen content is too high, which shields the active sites, resulting in reduced palladium exposure of the active sites and reduced dispersity. In some embodiments, the nitrogen-doped hollow carbon nanostructure is a nitrogen-doped hollow carbon nanosphere. In some embodiments, the hollow carbon nanospheres have a particle size of 20nm to 500nm, for example 30nm, 50nm, 70nm, 100nm, 130nm, 150nm, 170nm, 200nm, 230nm, 250nm, 300nm, 350nm, 400nm, 450nm, or any value in between. In some embodiments, the hollow carbon nanospheres have a particle size of 50nm to 100nm. Too high