CN-122006723-A - Porous carbon-assisted dispersed catalyst for preparing methanol by hydrogenation of carbon dioxide, preparation method and application thereof

CN122006723ACN 122006723 ACN122006723 ACN 122006723ACN-122006723-A

Abstract

The invention relates to a porous carbon-assisted dispersed catalyst for preparing methanol by hydrogenating carbon dioxide, a preparation method and application thereof. The method comprises the following steps of S1, carrying out dry mixing on metal salt and a porous carbon auxiliary agent to form mixed powder of the metal salt uniformly loaded on the porous carbon auxiliary agent, S2, carrying out Joule heating treatment on the mixed powder obtained in S1 in an inert atmosphere, carrying out in-situ decomposition on the metal salt to obtain precursor powder, and S3, calcining the precursor powder obtained in S2 in an oxygen-containing atmosphere to remove redundant carbon materials to obtain the catalyst for preparing methanol by hydrogenating carbon dioxide. The invention solves the technical problems of low catalytic activity, stability and reaction selectivity of the existing catalyst for preparing methanol by CO 2 hydrogenation.

Inventors

ZHANG XIAO
LIN SAISAI
SONG HAO
ZHANG YOU
GAO XIANG
ZHANG SHAORUI
LI WEIXIAN
SHAO YUNFEI
ZHENG CHENGHANG
LIU HONG
WENG WEIGUO
WU WEIHONG

Assignees

浙江大学
哈尔滨锅炉厂有限责任公司

Dates

Publication Date: 20260512
Application Date: 20251212

Claims (10)

1. The preparation method of the catalyst for preparing methanol by hydrogenation of carbon dioxide, which is dispersed by porous carbon, is characterized by comprising the following steps: s1, carrying out dry mixing on metal salt and a porous carbon auxiliary agent to form mixed powder of uniformly loading the metal salt on the porous carbon auxiliary agent; s2, carrying out Joule heating treatment on the mixed powder obtained in the step S1 in an inert atmosphere, and carrying out in-situ decomposition on metal salt to obtain precursor powder; and S3, calcining the precursor powder obtained in the step S2 in an oxygen-containing atmosphere, and removing redundant carbon materials to obtain the catalyst for preparing the methanol by hydrogenating the carbon dioxide.
2. The method according to claim 1, wherein the porous carbon auxiliary agent in the step S1 comprises at least one of activated carbon, conductive carbon black, graphene and carbon nanotubes, the metal salt comprises at least one of nitrate, acetate, oxalate, chloride and sulfate of metal, and the metal element in the metal salt comprises at least one of copper, zinc, aluminum, zirconium, titanium and manganese.
3. The method according to claim 1, wherein, In the S1, ball milling treatment is adopted for dry mixing, wherein the rotation speed of the ball milling treatment is 400-800 rpm, and the time is 15-120 min; S2, performing the Joule heating treatment in a conductive carrier, wherein the conductive carrier comprises a tungsten boat, a molybdenum boat or carbon paper, the Joule heating treatment mode comprises a pulse mode or a constant temperature mode, and in the Joule heating treatment, the heating rate is 100-10000 ℃ per second, and the heating time is 1S-10 min; and S3, calcining at 300-400 ℃ for 1-4 hours.
4. The preparation method of claim 1, wherein in S1, the mass ratio of the porous carbon auxiliary agent to the metal salt is 0.5:1 to 1.5:1.
5. A catalyst for producing methanol by hydrogenating carbon dioxide prepared by the method of any one of claims 1 to 4.
6. The catalyst for preparing methanol by hydrogenating carbon dioxide according to claim 5, wherein the catalyst is a copper-based multi-element metal oxide catalyst, the molar ratio of each metal element of the catalyst is Cu to Zn to Al to M=6 to 3 to x to y, wherein M is one of Zr, ti or Mn, the value of x is in the range of 0.1-0.9, the value of y is in the range of 0.1-2.1, and the total molar content of Cu and Zn is 60-90% of the total molar amount of metal.
7. The method according to claim 6, wherein the value of x is in the range of 0.2 to 0.7, and the value of y is in the range of 0.3 to 1.0.
8. The method according to claim 6, wherein M is Zr and the molar ratio of Cu to Zn to Al to Zr is 6:3:0.3:0.7.
9. Use of the catalyst for preparing methanol by hydrogenating carbon dioxide according to claim 7 or 8 in a reaction for preparing methanol by hydrogenating carbon dioxide.
10. The use according to claim 9, wherein the conditions for the reaction for preparing methanol by hydrogenating carbon dioxide are that the temperature is 180-240 ℃, the pressure is 3-6 MPa, the molar ratio of hydrogen to carbon dioxide is 2-4:1, and the total gas mass space velocity is 3000-30000 mL/g cat /h.

Description

Porous carbon-assisted dispersed catalyst for preparing methanol by hydrogenation of carbon dioxide, preparation method and application thereof Technical Field The invention relates to the technical field of catalysts, in particular to a catalyst for preparing methanol by hydrogenation of carbon dioxide, which is dispersed by porous carbon, a preparation method and application thereof. Background With the transition of the global energy system to low carbonization, the recycling of carbon dioxide is becoming an important focus of industrial field. The reaction for preparing methanol by carbon dioxide hydrogenation is taken as a path for converting the flue gas into high-valued chemical raw materials and green fuel, and has wide application prospect. The CO 2 molecule has higher stability, and the problems of low reaction activity, high energy consumption and the like need to be overcome in the hydroconversion of the CO 2 molecule. In the reaction process, the catalyst can effectively reduce the reaction energy barrier and promote the adsorption and activation of carbon dioxide. At present, the catalytic system used in the reaction of preparing methanol by hydrogenating carbon dioxide comprises a copper-based catalyst, an indium-based catalyst, an oxide solid solution catalyst and the like. Although these catalysts exhibit certain catalytic capabilities in the carbon dioxide adsorption, activation and hydrogenation steps, they still face the problem that the metal particles are easily sintered at high temperatures and the active interfaces are difficult to regulate. The preparation of metal oxide catalysts generally uses calcination or hydrothermal heat treatment to decompose the precursor to form the oxide catalyst. However, these methods are limited by low temperature rising rate, long treatment time and high energy consumption, and the catalyst exposed at high temperature for a long time is easy to generate phenomena of collapse of pore channel structure, agglomeration of active phase and the like, so that further improvement of reaction activity and structural stability is restricted. In recent years, joule heating treatment has been receiving attention in the field of energy materials due to the characteristics of high temperature rising rate, simple process, easy amplification, and the like. However, the current research has focused on supported electrode material systems with good electrical conductivity, and their application is still challenging for less conductive metal oxide powders. Instantaneous local overheating easily occurs in the process of the Joule heat treatment, and the phase change, doping and active interface formation of the powder catalyst are affected, so that the powder catalyst is restricted from being rapidly synthesized by the Joule heat treatment. Therefore, a stable conductive network structure is constructed in the metal oxide catalyst system, so that the powder layer is uniformly heated under the action of current, and the method is a technical problem of realizing large-scale application of the Joule heating technology in the technology of preparing methanol by hydrogenating carbon dioxide. Disclosure of Invention The invention provides a preparation method of a porous carbon-assisted dispersed catalyst for preparing methanol by hydrogenating carbon dioxide, which aims to solve the technical problems of low catalytic activity, stability and reaction selectivity of the existing catalyst for preparing methanol by hydrogenating CO 2. The technical scheme adopted by the invention is as follows: A preparation method of a porous carbon-assisted dispersion catalyst for preparing methanol by hydrogenating carbon dioxide comprises the following steps of S1, carrying out dry mixing on metal salt and a porous carbon auxiliary agent to form mixed powder of the metal salt uniformly loaded on the porous carbon auxiliary agent, S2, carrying out Joule heating treatment on the mixed powder obtained in S1 in an inert atmosphere, carrying out in-situ decomposition on the metal salt to obtain precursor powder, and S3, calcining the precursor powder obtained in S2 in an oxygen-containing atmosphere to remove redundant carbon materials to obtain the catalyst for preparing methanol by hydrogenating carbon dioxide. According to the method, the porous carbon auxiliary agent (active carbon, carbon black and the like) is introduced in the preparation process of the catalyst, so that the technical problem that the metal oxide precursor of the insulation/semiconductor is difficult to prepare rapidly by directly utilizing the Joule heating technology is solved, and meanwhile, the problem that nano particles are easy to agglomerate at high temperature is solved by utilizing the pore structure of the carbon material. In the present invention, the porous carbon is not only a carrier, but also a conductive path is constructed in the reaction, and the current generates high temperature of 1000-3000 ℃ through