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CN-122006724-A - Copper-based catalyst for preparing hydrogen by methanol pyrolysis and preparation method thereof

CN122006724ACN 122006724 ACN122006724 ACN 122006724ACN-122006724-A

Abstract

The invention belongs to the technical field of synthetic gas chemical industry and catalytic materials, and particularly relates to a copper-based catalyst for preparing hydrogen by methanol pyrolysis and a preparation method thereof. The catalyst comprises a metal active component, a catalyst auxiliary agent and a catalyst carrier, wherein the metal active component is copper, one of copper nitrate/copper carbonate/copper sulfate is selected, the composition range is 55-75%, the catalyst carrier is Al, an Al source comprises at least one of Al 3+ salt, the composition range is 10-20%, the catalyst auxiliary agent comprises at least one of zinc, magnesium and barium, and the composition range is 1-20%. Compared with the prior art, the method has the advantages that particles are recombined through a dissolving-reprecipitating process, crystal defects are reduced, a more stable precursor structure is formed, cu species are promoted to be deposited more uniformly during subsequent precipitation with CuZnAl salt, so that the synergistic effect between Cu-Zn-Al is enhanced, and the activity and stability of the catalyst are effectively improved.

Inventors

  • SHI YULIN
  • LI YANG
  • TAN LI
  • ZHANG HAORAN
  • JIA HAOYANG
  • CHENG XUEBIN
  • ZHANG YU
  • ZHANG LEI

Assignees

  • 浙江思欣通氢能科技有限公司

Dates

Publication Date
20260512
Application Date
20251223

Claims (7)

  1. 1. The copper-based catalyst for preparing hydrogen by methanol pyrolysis is characterized by comprising a metal active component, a catalyst auxiliary agent and a catalyst carrier; wherein the metal active component is copper, and one of copper nitrate/copper carbonate/copper sulfate is selected, and the composition range is 55-75%; Wherein the catalyst carrier is Al, and the Al source comprises at least one of Al 3+ salt, and the composition range is 10-20%; wherein the catalyst auxiliary agent comprises at least one of zinc, magnesium and barium, and the composition range is 1-20%.
  2. 2. The catalyst according to claim 1, wherein the specific surface area of the catalyst is 56-88m 2 /g, the pore volume is 0.28-0.67cm 3 /g, and the pore diameter is 13-29nm.
  3. 3. A method for preparing a copper-based catalyst for the production of hydrogen by the cleavage of methanol according to any one of claims 1 to 2, comprising the steps of: (1) Weighing Zn 2+ 、Al 3+ and Mg 2+ /Ba 2+ metal salt solutions with corresponding mass to prepare a salt solution A; (2) Dissolving a first precipitant, namely a mixture of sodium bicarbonate and sodium hydroxide, to prepare an alkali solution a; (3) Weighing Cu 2+ ,Zn 2+ and Al 3+ metal salt solution with corresponding mass to prepare a salt solution B; (4) Dissolving a second precipitant in water to prepare an alkali solution b, wherein the second precipitant comprises one or a mixture of sodium carbonate, sodium bicarbonate and sodium hydroxide; (5) Under high-speed shearing, carrying out an emulsification reaction on the salt solution A and the precipitator a, controlling the precipitation condition pH=6-10 in the reaction process, and obtaining suspension C at the precipitation temperature of 20-50 ℃ and the shearing speed of 10000-15000 r/min; (6) Adding the suspension C, the salt solution B and the alkali liquor B into a reaction kettle through a flow pump respectively, regulating the flow of the alkali liquor B to enable the pH value to be 6-8, feeding for 40-60min, reacting at 60-90 ℃, stirring at 100-200r/min, reducing the stirring speed after feeding is completed, and standing and ageing for 4-8h; (7) Drying, namely drying the washed sample at 60-90 ℃ for 12 hours; (8) Roasting, namely placing the mixture in a high-temperature furnace, heating the mixture from room temperature to 250-550 ℃ in a programmed manner, roasting the mixture at a constant temperature for 4-8 hours, and cooling the mixture to room temperature to obtain a roasting product; (9) And uniformly mixing the roasting product with 1-5% of graphite to obtain a mixture, and tabletting and forming the mixture to obtain the catalyst.
  4. 4. The method according to claim 3, wherein in the step (1), the molar ratio of Zn 2+ /Al 3+ in the salt solution A is 3:1 to 1:1.
  5. 5. The method according to claim 3 or 4, wherein in the step (1), the alkaline earth metal salt solution is nitrate in an amount of 1% to 5%.
  6. 6. The method according to claim 3, wherein in the step (3), the molar ratio of the salt solution B to Zn 2+ in the salt solution A is 2:7 to 5:7.
  7. 7. A method according to claim 3, wherein in step (8), the temperature programmed rate is 1 to 5 ℃ per minute.

Description

Copper-based catalyst for preparing hydrogen by methanol pyrolysis and preparation method thereof Technical Field The invention belongs to the technical field of synthetic gas chemical industry and catalytic materials, and particularly relates to a copper-based catalyst for preparing hydrogen by methanol pyrolysis and a preparation method thereof. Background At present, methanol is considered to be an ideal hydrogen carrier because of the advantages of simple molecular structure, high hydrocarbon ratio, lower reforming temperature, capability of being stored and transported under simple and safe conditions, and the like. The hydrogen production by methanol is mainly carried out by two methods, namely, methanol pyrolysis hydrogen production (CH 3OH＝2H2 +CO) and methanol steam reforming (CH 3OH+H2O＝CO2+3H2), and compared with a methanol pyrolysis reactant, the methanol steam reforming reaction is more complex in energy, relatively simple in methanol pyrolysis reaction and less in energy consumption. For the selection of a catalyst for preparing hydrogen from methanol, the conventional CuZnAl-based catalyst is widely applied at present, such as patent CN118950004A, and a CuZnAlGa catalyst, a preparation method and application thereof in the aspect of preparing hydrogen by catalysis are disclosed, namely, methanol vapor is subjected to reforming reaction to generate hydrogen under the action of a composite material catalyst containing Cu, zn, al, ga metal components, and the catalyst has higher activity and low CO selectivity. Patent CN118162140A discloses a preparation method and application of a hydrotalcite-like CuZnAl-based methanol reforming hydrogen production catalyst, the catalyst has good crystallinity and high dispersity of active components, excellent catalytic methanol reforming hydrogen production reaction performance is shown, patent CN118663340A discloses a preparation method of a low-copper methanol reforming hydrogen production catalyst, and the prepared CuO/ZnO-Al 2O3 composite oxide powder has higher low-temperature activity and thermal stability. However, the CuZnAl-based catalyst has less research on the aspect of hydrogen production by methanol pyrolysis and has not wide application. Therefore, the development of the high-activity methanol cracking catalyst has profound significance in the field of fine chemical engineering. Disclosure of Invention The invention aims to provide a high-activity and high-stability copper-based catalyst for preparing hydrogen by cracking methanol. The catalyst comprises a catalyst metal active component, a catalyst auxiliary agent and a catalyst carrier; wherein the metal active component is copper, which can be one of copper nitrate/copper carbonate/copper sulfate, and the composition range is 55-75%; Wherein the catalyst carrier is Al, and the Al source comprises at least one of Al 3+ salt, and the composition range is 10-20%; wherein the catalyst auxiliary agent comprises at least one of zinc, magnesium and barium, and the composition range is 1-20%; Wherein, the specific surface area of the catalyst is 56-88m 2/g, the pore volume is 0.28-0.67cm 3/g, and the pore diameter is 13-29nm; The XRD pattern shows obvious diffraction peak of CuO characteristic, and the action of Zn and alumina carrier generates hydrotalcite-like compound, which is favorable for stabilizing the catalyst carrier structure and preventing alumina from phase change and sintering at high temperature, thereby maintaining higher specific surface area. The addition of a proper amount of ZnO can adjust the electronic state and dispersity of Cu, expose more active sites, facilitate the adsorption of methanol and the activation of C-H bonds, and promote the cracking reaction. The alkaline earth metal magnesium calcium barium can regulate and control the acidity of the carrier Al 2O3 or the composite oxide, and inhibit side reactions. Greatly reduces the dehydration reaction of methanol catalyzed by strong acid sites, thereby inhibiting the generation of by-product dimethyl ether (DME) and improving the selectivity of target products (H 2 and CO). In order to achieve the above object, the present invention further provides a method for preparing a copper-based catalyst for producing hydrogen by methanol pyrolysis, wherein the method comprises the following steps: (1) Weighing Zn 2+、Al3+ and Mg 2+/Ba2+ metal salt solutions with corresponding mass to prepare salt solution A. (2) Dissolving a first precipitant, namely a mixture of sodium bicarbonate and sodium hydroxide, to prepare an alkali solution a; (3) And weighing Cu 2+,Zn2+ and Al 3+ metal salt solution with corresponding mass to prepare a salt solution B. (4) Dissolving a second precipitant in water to prepare an alkali solution b, wherein the second precipitant comprises one or a mixture of sodium carbonate, sodium bicarbonate and sodium hydroxide; (5) Under high-speed shearing, carrying out an emulsification reaction on the salt solution