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CN-121988333-A - Desolventizing copper-based perovskite catalyst, and preparation method and application thereof

CN121988333ACN 121988333 ACN121988333 ACN 121988333ACN-121988333-A

Abstract

The invention relates to the field of functional material and energy conversion, in particular to a desolventizing copper-based perovskite catalyst, a preparation method and application thereof, comprising a substrate with a perovskite structure and Cu metal particles desolventized on the surface of the substrate, wherein the catalyst element comprises La, cu, cr and O, and the molar ratio of La, cu and Cr satisfies La: cu+Cr=0.8-1.2:1. Is obtained by hydrogen reduction treatment of perovskite precursor with the general formula of La 0.9 Cu x Cr 1‑ x O 3‑δ , wherein x is more than 0 and less than or equal to 0.5. The catalyst obtained by the invention has excellent stability, a byproduct CO can not be detected in the methanol steam reforming reaction under the action of the catalyst, methanol can be converted into CO 2 and H 2 with high selectivity, meanwhile, the desolventizing perovskite structure provides a stable structural framework for a Cu active phase, and a tight metal-carrier strong interaction exists between the desolventizing perovskite structure and a carrier, so that sintering agglomeration of the active phase is inhibited, and the hydrogen production stability is greatly improved.

Inventors

  • SUN SHUANGCHENG
  • SUN ZHIQIANG
  • LI LIN
  • WEN SHUANG
  • LI XIAOCHUN
  • SUN CHAO
  • YU SHUFAN
  • ZHANG HUAN

Assignees

  • 株洲国创轨道科技有限公司
  • 中南大学

Dates

Publication Date
20260508
Application Date
20260326

Claims (10)

  1. 1. A desolventizing copper-based perovskite catalyst, which is characterized by comprising a substrate with a perovskite structure and Cu metal particles desolventized on the surface of the substrate; The catalyst element composition comprises La, cu, cr and O, wherein the molar ratio of La to Cu to Cr satisfies La to Cu+Cr=0.8-1.2:1.
  2. 2. The method for preparing the desolventized copper-based perovskite catalyst according to claim 1, wherein the desolventized copper-based perovskite catalyst is obtained by reducing a perovskite precursor with a general formula of La 0.9 Cu x Cr 1-x O 3-δ with hydrogen, wherein x is more than 0 and less than or equal to 0.5.
  3. 3. The method for preparing a desolventizing copper-based perovskite catalyst according to claim 2, wherein the hydrogen reduction treatment is adopted to desolventize Cu ions partially or totally doped at the B site of the perovskite from the crystal lattice in the form of Cu metal particles, and the Cu ions are highly dispersed on the surface of the La-Cr-O-based perovskite substrate having oxygen vacancies.
  4. 4. The method for preparing a desolventized copper-based perovskite catalyst according to claim 2, wherein the Cu metal particles have a particle size of 20 to 100 nm.
  5. 5. The method for preparing the desolventized copper-based perovskite catalyst according to claim 2, which is characterized by comprising the following steps: (1) Preparing La 0.9 Cu x Cr 1-x O 3-δ perovskite precursor by adopting a sol-gel method, mixing La source, cu source, cr source, complexing agent and solvent, stirring to form gel, and then drying, grinding and calcining; (2) And (3) performing temperature programming reduction treatment on the precursor obtained in the step (1) in H 2 /Ar induced by plasma discharge to obtain the catalyst.
  6. 6. The method for preparing a copper-removing perovskite catalyst according to claim 5, wherein in the step (1), the stirring treatment temperature is 70-90 ℃ and the time is 1.5-3 hours, the drying temperature is 120-200 ℃, the drying time is 3-10 hours, the calcining temperature is 600-900 ℃ and the calcining time is 2-6 hours.
  7. 7. The method of claim 5, wherein in the step (1), the La source comprises La (NO 3 ) 3 or LaCl 3 ), the Cu source comprises Cu (NO 3 ) 2 or CuCl 2 ), the Cr source comprises Cr (NO 3 ) 3 or CrCl 3 ), and the complexing agent comprises citric acid, maleic acid, oxalic acid or polyvinyl alcohol.
  8. 8. The method for preparing a copper-removing perovskite catalyst according to claim 5, wherein in the step (2), the plasma discharge power is 30-100W, the reduction treatment temperature is 200-900 ℃ and the time is 1-8h, and the hydrogen volume concentration in the hydrogen/nitrogen atmosphere is 5% -25%.
  9. 9. Use of a desolventized copper-based perovskite catalyst according to claim 1 as a catalyst for the production of hydrogen from methanol.
  10. 10. A method for producing hydrogen from methanol, which is characterized by comprising the steps of mixing methanol with deionized water, vaporizing, and contacting the mixture with the desolventizing copper-based perovskite catalyst according to claim 1 under reaction conditions; the methanol reforming reaction condition comprises that the molar ratio of deionized water to methanol is 0.5-3, the feeding rate of raw materials of aqueous methanol solution is 0.005-0.01mL/min, and the reaction temperature is 180-350 ℃.

Description

Desolventizing copper-based perovskite catalyst, and preparation method and application thereof Technical Field The invention relates to the field of functional materials and energy conversion, in particular to a desolventizing copper-based perovskite catalyst, a preparation method and application thereof. Background Hydrogen is a promising energy carrier, and is receiving attention by virtue of its high energy density and zero pollution emission properties. However, at the same time, the problems of high energy consumption, high cost, high safety risk and the like still exist in the storage and transportation of hydrogen energy, and these factors restrict the large-scale application of the hydrogen energy in the fields of aviation, aerospace, automobiles and the like. Methanol is used as a hydrogen carrier with rich reserves, has the advantages of low conversion temperature (less than 300 ℃), convenient storage and transportation, high H/C molar ratio and the like, is hopeful to solve the problems of hydrogen storage and utilization by adopting methanol reforming in-situ preparation, and provides a feasible method in the field of mobile terminal energy supply, in particular to hydrogen supply for a hydrogen fuel cell. Methanol reforming hydrogen production is one of ideal technical routes for distributed hydrogen production such as vehicle-mounted fuel cells. Copper-based catalysts (e.g., industrial Cu/ZnO/Al 2O3) are widely used due to their high activity and selectivity, but they have problems of easy sintering and deactivation of copper particles at high temperatures, higher CO concentration of byproducts, etc. In recent years, perovskite-type oxides (ABO 3) have received increasing attention for their high degree of controllability, high conductivity, rapid surface oxygen exchange and oxygen ion diffusion. Active metal (such as Cu, co, ni, fe) is doped into perovskite crystal lattice, and then is reduced to be stripped from the crystal lattice, so that the highly-dispersed and anti-sintering metal nano-particles with strong interaction with a carrier can be obtained, and a potential thought is provided for long-period stability of a methanol hydrogen production reaction. Disclosure of Invention In order to solve the problems of insufficient catalyst activity, poor stability, higher byproduct CO concentration and the like in the conventional hydrogen production by methanol reforming, the first aim of the invention is to provide a desolventizing perovskite type desolventizing copper-based perovskite catalyst which has the advantages of good stability and negligible product CO selectivity. In order to achieve the above object, an aspect of the present invention provides a desolventizing copper-based perovskite catalyst including a matrix having a perovskite structure and Cu metal particles desolventized from the matrix; Wherein the element composition of the catalyst comprises La, cu, cr and O, the molar ratio of La, cu and Cr is satisfied, n (La) n (Cu+Cr) = (0.8-1.2) 1. Preferably, the molar ratio of La, cu, cr satisfies n (La): n (cu+cr) =0.9:1. The second object of the invention is to provide a method for preparing the desolventized copper-based perovskite catalyst. The catalyst is obtained by hydrogen reduction treatment of a perovskite precursor with a general formula of La 0.9CuxCr1-xO3-δ, wherein x is more than 0 and less than or equal to 0.5; preferably, the mol ratio of Cu element to Cr element in the catalyst is 3:7. And (3) adopting hydrogen reduction treatment to enable part or all of Cu ions doped at the B site of the perovskite to be desolventized from a crystal lattice in the form of Cu metal particles, and highly dispersing the Cu ions on the surface of the La-Cr-O-based perovskite matrix with oxygen vacancies. The particle size of the Cu metal particles is 20-100 nm, preferably 30-70nm. The catalyst takes A-site defect perovskite La 0.9CuxCr1-xO3-δ as a precursor, and selectively desolventizes B-site Cu ions by controlling plasma discharge power, reduction temperature and time to form a highly dispersed Cu metal active phase with strong interaction with a perovskite carrier, so that the desolventized copper-based perovskite catalyst with high activity, high selectivity and excellent stability is obtained. The third object of the invention is to provide the application of the desolventized copper-based perovskite catalyst in hydrogen production by methanol reforming. The invention discovers that the desolventizing perovskite catalyst has high catalytic activity and stability, obviously improves the problem of Cu active phase deactivation in the process of preparing hydrogen by reforming methanol, can realize high-efficiency stable hydrogen preparation of methanol, and improves the selectivity and hydrogen yield of the product. A method for preparing a desolventized copper-based perovskite catalyst, comprising the following steps: (1) Preparing La 0.9CuxCr1-xO3-δ perovskite precursor by ad