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CN-122006708-A - Rare earth silicate supported ammonia decomposition catalyst and preparation method and application thereof

CN122006708ACN 122006708 ACN122006708 ACN 122006708ACN-122006708-A

Abstract

The application discloses a rare earth silicate supported ammonia decomposition catalyst and a preparation method and application thereof, belonging to the technical field of catalyst preparation and heterogeneous catalysis. The catalyst comprises a carrier and an active component, wherein the carrier is rare earth silicate, and the active component is a single metal or a double metal or a multi-metal combination of iron, cobalt, nickel and ruthenium. In the preparation method, the active components are promoted to be uniformly dispersed on the surface of the rare earth silicate carrier through an optimized impregnation-calcination process. The constructed catalyst has strong metal-carrier interaction, shows excellent ammonia decomposition activity in a temperature range of 350-650 ℃, and has excellent long-term stability. The technology has the advantages of simple preparation flow, low cost and environmental friendliness, is suitable for being applied to the fields of distributed hydrogen production systems and ammonia decomposition tail gas treatment, and has outstanding industrial application prospect and market development potential.

Inventors

  • LIU LIN
  • JU XIAOHUA
  • HE TENG
  • CHEN PING

Assignees

  • 中国科学院大连化学物理研究所

Dates

Publication Date
20260512
Application Date
20251230

Claims (10)

  1. 1. The preparation method of the rare earth silicate supported ammonia decomposition catalyst is characterized by comprising the following steps of: And (3) putting the rare earth silicate carrier into a solution containing an active component precursor for impregnation, and drying, roasting and reducing the impregnated rare earth silicate carrier to obtain the soil silicate supported ammonia decomposition catalyst.
  2. 2. The method according to claim 1, wherein the rare earth silicate support is at least one selected from lanthanum silicate, cerium silicate, praseodymium silicate, neodymium silicate, samarium silicate, europium silicate, gadolinium silicate, terbium silicate, dysprosium silicate, holmium silicate, erbium silicate, ytterbium silicate, lutetium silicate, yttrium silicate, scandium silicate.
  3. 3. The preparation method according to claim 1, wherein the active component precursor is at least one selected from the group consisting of ruthenium acetylacetonate, ruthenium carbonyl, potassium ruthenate, sodium ruthenate, ruthenium iodide, ruthenium nitrosylnitrate, ruthenium acetate, ammonium ruthenate chloride, ruthenium chloride, iron nitrate, iron chloride, iron sulfate, cobalt nitrate, cobalt chloride, cobalt carbonate, cobalt sulfate, cobalt acetate, cobalt carbonyl, nickel nitrate, nickel chloride, nickel sulfate, nickel carbonate, nickel acetate, and nickel oxalate; Preferably, the solvent in the solution containing the active component precursor is selected from at least one of water, ethanol, acetone, tetrahydrofuran.
  4. 4. The preparation method of claim 1, wherein the ratio of the rare earth silicate carrier to the solution containing the active component precursor is 1 g:1-10 ml; Preferably, the impregnation conditions comprise impregnating for 0.5-48 hours at 10-80 ℃; preferably, the drying condition comprises drying at 30-150 ℃ for 1-48 hours.
  5. 5. The method according to claim 1, wherein the calcination is carried out in an inert gas atmosphere at a calcination temperature of 300 to 1200 ℃ for a calcination time of 1 to 48 hours, and a volume space velocity of the inert gas of 100 to 10000 mL g cat 1 h 1 。
  6. 6. The method according to claim 1, wherein the reducing conditions include a reducing temperature of 50 to 850 ℃ and a reducing time of 0.1 to 24 hours in an atmosphere of a reducing gas having a volume space velocity of 100 to 10000 mL g cat 1 h 1 ; Preferably, the reducing gas is hydrogen and/or ammonia.
  7. 7. The rare earth silicate supported ammonia decomposition catalyst obtained by the production method according to any one of claims 1 to 6, characterized in that the rare earth silicate supported ammonia decomposition catalyst comprises a carrier and an active component; wherein the carrier is rare earth silicate; The active component is at least one of iron, cobalt, nickel and ruthenium.
  8. 8. The rare earth silicate supported ammonia decomposition catalyst according to claim 7, wherein the mass content of the active component in the rare earth silicate supported ammonia decomposition catalyst is 0.5-60 wt%; when the active component is ruthenium and other elements, the molar ratio of ruthenium to other elements is 1:10-100, wherein the other elements are at least one of iron, cobalt and nickel.
  9. 9. Use of at least one of the rare earth silicate supported ammonia decomposition catalyst obtained by the production method according to any one of claims 1 to 6, the rare earth silicate supported ammonia decomposition catalyst according to claim 7 or 8 for catalyzing ammonia decomposition, characterized by comprising: and (3) contacting ammonia gas or feed gas containing ammonia with the rare earth silicate supported ammonia decomposition catalyst to perform catalytic reaction to generate hydrogen and nitrogen.
  10. 10. The use according to claim 9, wherein the ammonia gas in the feed gas containing ammonia has a volume concentration of 0.1% -100%; preferably, the catalytic reaction is carried out in a fixed bed reactor or a fluidized bed reactor; Preferably, the conditions of the catalytic reaction comprise a reaction pressure of 0.1-10 MPa, a reaction temperature of 300-800 ℃ and a space velocity of 1000-100000 mL g of ammonia or raw material gas containing ammonia cat 1 h 1 。

Description

Rare earth silicate supported ammonia decomposition catalyst and preparation method and application thereof Technical Field The application relates to a rare earth silicate supported ammonia decomposition catalyst and a preparation method and application thereof, belonging to the technical field of catalyst preparation and heterogeneous catalysis. Background The hydrogen energy is taken as a zero-carbon and high-efficiency secondary energy source and is regarded as a core carrier for supporting energy structure transformation. However, the large-scale application of hydrogen energy is always limited by the technical bottleneck of the storage and transportation link, and the energy consumption is large and potential safety risks exist. Ammonia is used as an ideal hydrogen energy carrier and gradually becomes a research hot spot, wherein the mass hydrogen storage density is up to 17.6 wt%, the far-ultrahigh pressure gaseous hydrogen and liquid hydrogen are in liquid state at normal temperature and normal pressure, the low-cost storage and transportation can be realized by utilizing the existing chemical storage tank and transportation pipe network, and more importantly, the technology of synthesizing ammonia is developed for centuries, the technology is mature, the large-scale cost is low, and a solid foundation is provided for the large-scale preparation of ammonia. The ammonia decomposition hydrogen production reaction is used as a key link for connecting ammonia and hydrogen energy, and the efficiency directly determines the conversion efficiency of a hydrogen energy carrier. The reaction is a strong endothermic process, and the performance of the catalyst is the core for reducing the reaction activation energy and improving the conversion rate. Currently, ammonia decomposition catalysts are mainly classified into two types, noble metal-based catalysts typified by ruthenium and non-noble metal-based catalysts typified by iron, cobalt, and nickel. However, ruthenium has high market price, global reserves are concentrated in a few areas, and large-scale application is limited, and the cost of iron, cobalt and nickel is only one percent or even lower than that of ruthenium, but the low-temperature activity is insufficient, and high-temperature metal particles are easy to sinter. Therefore, the development of the catalyst which has low-temperature high activity, high-temperature stability, sintering resistance and controllable cost becomes a key for breaking through the technical bottleneck of ammonia decomposition hydrogen production. The catalyst carrier is used as the supporting framework of the active component, and the comprehensive performance of the catalyst is directly affected by regulating and controlling the dispersibility, the electronic state and the interfacial interaction of the active metal. However, carbon materials such as graphene, carbon nanotubes and the like can anchor metal nano particles through coordination by virtue of functional groups such as hydroxyl groups, carboxyl groups and the like on the surfaces, but have poor high temperature resistance, are easy to generate carbon deposition reaction, cause active site coverage and finally irreversibly inactivate the catalyst. The traditional oxide has low price, high specific surface area, acidity or alkalinity and other characteristics, but the catalytic activity is still low, and active metal agglomeration is easy to cause. Disclosure of Invention In order to solve the problem that the catalyst in the prior art for preparing hydrogen by ammonia decomposition is limited by a carrier and is difficult to consider high activity, high temperature resistance and low cost, the application provides a preparation technical scheme of a rare earth silicate supported ammonia decomposition catalyst, which adopts rare earth silicate as a carrier and has unique surface chemical properties, acid-base sites capable of being accurately regulated and controlled and excellent chemical stability. The catalyst prepared based on the carrier not only realizes the high dispersion of active components, but also remarkably enhances the adsorption and activation capability to ammonia by constructing strong metal-carrier interaction, and simultaneously, the strong interaction can effectively anchor active metal and inhibit the sintering phenomenon of the active metal at high temperature, thereby fundamentally solving the key bottleneck of the catalyst in the aspects of activity and stability. The application adopts the following technical scheme: according to a first aspect of the present application, there is provided a method for preparing a rare earth silicate supported ammonia decomposition catalyst, comprising: And (3) putting the rare earth silicate carrier into a solution containing an active component precursor for impregnation, and drying, roasting and reducing the impregnated rare earth silicate carrier to obtain the soil silicate supported ammonia decomp