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CN-121976242-A - Iridium-containing catalyst, preparation and post-treatment methods thereof and application thereof

CN121976242ACN 121976242 ACN121976242 ACN 121976242ACN-121976242-A

Abstract

The invention provides an iridium-containing catalyst, a preparation and post-treatment method and application thereof. The iridium-containing catalyst contains alkali metal and/or alkaline earth metal and iridium, and the molar ratio of the alkali metal and/or alkaline earth metal to iridium is 0.1-100:1. The preparation method of the iridium-containing catalyst comprises the steps of mixing an alkali metal and/or alkaline earth metal precursor and an iridium precursor to obtain a mixture, heating the mixture to react, cooling after the reaction, and grinding or dispersing a product to obtain the iridium-containing catalyst. The invention also provides the iridium-containing catalyst prepared by the method, a post-treatment method and application thereof. The iridium-containing catalyst provided by the invention has excellent physical and chemical characteristics when being used for sensing, mechanics and structural materials, and has the characteristics of high specific surface area, high activity and good stability when being used for electrocatalytic, photocatalytic and other catalytic reactions.

Inventors

  • TIAN BOYUAN
  • DENG ZHANFENG
  • YANG LAN

Assignees

  • 北京怀柔实验室
  • 北京智慧能源研究院

Dates

Publication Date
20260505
Application Date
20241106

Claims (16)

  1. 1. An iridium-containing catalyst, wherein the iridium-containing catalyst contains an alkali metal and/or alkaline earth metal and iridium in a molar ratio of 0.1 to 100:1, preferably 0.1 to 5:1, more preferably 0.15:1 to 2:1; Preferably, the iridium-containing catalyst has a growth advantage in one or a combination of two or more of the following crystal orientations: (-112)、(110)、(101)、(200)、(211)、(112)。
  2. 2. The iridium-containing catalyst according to claim 1, wherein the iridium-containing catalyst is potassium iridium and/or cesium iridium, preferably the potassium iridium is K 0.25 IrO 2 , which has growth advantage in the (-112) crystal direction; Preferably, the cesium iridium oxide is Cs 0.25 IrO 2 , which has a growth advantage in the (-112) crystal direction.
  3. 3. The iridium-containing catalyst according to claim 1, wherein the alkali metal comprises one or a combination of two or more of lithium, sodium, potassium, rubidium, cesium; The alkaline earth metal comprises one or more of magnesium, calcium, strontium and barium.
  4. 4. An iridium-containing catalyst according to claim 3, wherein the alkali metal comprises potassium and/or cesium and the alkaline earth metal comprises magnesium.
  5. 5. Iridium-containing catalyst according to any one of claims 1 to 4, wherein the iridium-containing catalyst has a length of 5 nm to 5 microns (further preferably 20nm to 1 micron) and a width of 2 nm to 50 nm (further preferably 2 nm to 10 nm).
  6. 6. The process for producing an iridium-containing catalyst as claimed in any one of claims 1 to 5, which comprises the steps of: Mixing an alkali metal and/or alkaline earth metal precursor with an iridium precursor in a molar ratio of 0.01:1 to 1000:1 to obtain a mixture; heating the mixture to the reaction temperature of 350-900 ℃ and maintaining for 0.1s-900h for reaction; and cooling after the reaction, grinding or dispersing the product to obtain the iridium-containing catalyst.
  7. 7. The production method according to claim 6, wherein the alkali metal and/or alkaline earth metal precursor comprises one or a combination of two or more of an organic salt and an inorganic salt of an alkali metal and/or an alkaline earth metal, preferably the alkali metal and/or alkaline earth metal precursor comprises one or a combination of two or more of a nitrate, a persulfate, a carbonate, a hydrochloride, and a phosphate of an alkali metal and/or an alkaline earth metal; Preferably, the method comprises the steps of, The precursor of lithium is one or more than two of organic lithium salt and inorganic lithium salt, preferably one or more than two of lithium nitrate, lithium persulfate and lithium carbonate; the sodium precursor is selected from one or more of organic sodium salt and inorganic sodium salt, preferably, the sodium precursor is one or more of sodium nitrate, sodium persulfate and sodium carbonate; The precursor of potassium is selected from one or more than two of organic potassium salt and inorganic potassium salt, preferably, the precursor of potassium is one or more than two of potassium nitrate, potassium persulfate, potassium chloride and potassium phosphate; The precursor of rubidium is selected from one or more of organic rubidium salt and inorganic rubidium salt, preferably one or more of rubidium nitrate, rubidium persulfate and rubidium carbonate; the precursor of cesium is selected from one or more of organic cesium salt and inorganic cesium salt, preferably one or more of cesium nitrate, cesium persulfate and cesium carbonate; the magnesium precursor is one or more of organic magnesium salt and inorganic magnesium salt, preferably one or more of magnesium nitrate, magnesium persulfate and magnesium carbonate; The precursor of the calcium is one or a combination of more than two of organic calcium salt and inorganic calcium salt, preferably, the precursor of the calcium is one or a combination of more than two of calcium nitrate, calcium persulfate and calcium carbonate; The strontium precursor is selected from one or more of organic strontium salt and inorganic strontium salt, preferably one or more of strontium nitrate, strontium persulfate and strontium carbonate; The precursor of barium is one or more of organic barium salt and inorganic barium salt, preferably one or more of barium nitrate, barium persulfate and barium carbonate.
  8. 8. The production method according to claim 6, wherein the precursor of iridium is one or more selected from the group consisting of elemental iridium, chloroiridium (IV) acid and a hydrate thereof, chloroiridium (III) acid and a hydrate thereof, iridium (IV) acetate and a hydrate thereof, iridium (III) acetate and a hydrate thereof, chloroiridium (IV) sodium acid and a hydrate thereof, chloroiridium (III) sodium acid and a hydrate thereof, chloroiridium (IV) potassium acid and a hydrate thereof, chloroiridium (III) potassium acid and a hydrate thereof, chloroiridium (IV) ammonia and a hydrate thereof, chloroiridium (III) ammonia and a hydrate thereof.
  9. 9. The preparation method according to claim 6, wherein the molar ratio of the alkali metal and/or alkaline earth metal precursor to iridium precursor is 0.1-100:1, preferably 5:1-20:1, more preferably 10:1, based on the molar amount of alkali metal and/or alkaline earth metal, iridium molar amount, respectively.
  10. 10. The production method according to claim 6, wherein the reaction temperature is 500 to 600 ℃; preferably, the rate of temperature rise is no more than 200 ℃ per minute; preferably, the maintenance time is 3-6 hours.
  11. 11. The preparation method according to claim 6, wherein the heating, maintaining, and cooling processes are repeated at least 2 times, i.e., after cooling, the temperature is again raised to the reaction temperature, maintained for a certain period of time, and then cooled again.
  12. 12. The preparation method according to claim 6, wherein the preparation method further comprises pre-sintering and/or drying the mixture at 60-400 ℃; Preferably, the pre-sintering time is greater than or equal to 1 minute, more preferably 1 to 4 hours; Preferably, the drying time is not less than 10 minutes, more preferably 6 to 12 hours.
  13. 13. The method for post-treating an iridium-containing catalyst as claimed in any one of claims 1 to 5, wherein the post-treatment method is a method for post-treating the iridium-containing catalyst with a solution; The hydrogen ion concentration of the solution is 10 -15 mol/L to 10mol/L, preferably 0.1mol/L to 5mol/L, further preferably 0.5mol/L to 2mol/L; preferably, the solution is selected from one or a mixture of more than two of acid, alkali, water, organic solvent and metal ion salt solution.
  14. 14. The post-processing method according to claim 13, wherein the post-processing method comprises: Mixing the solution with an iridium-containing catalyst, preferably, the mixing mode comprises one or more than two of soaking, stirring, ultrasonic treatment, cell disruption and ball milling; standing the mixture for 5 minutes to 72 hours, stirring, and then performing ultrasonic treatment or cell disruption; Centrifuging, standing, settling and filtering the ultrasonic or cell disruption product to obtain a solid product, and drying to obtain a final product.
  15. 15. A post-treatment method according to claim 14, wherein the time of sonication or cell disruption is between 5 minutes and 10 hours, preferably 1 hour.
  16. 16. Use of an iridium-containing catalyst as claimed in any one of claims 1 to 5 in a water electrolysis membrane electrode or galvanic pile.

Description

Iridium-containing catalyst, preparation and post-treatment methods thereof and application thereof Technical Field The invention relates to an iridium-containing catalyst, a preparation and post-treatment method and application thereof, and belongs to the technical field of materials. Background In recent years, the international society pays attention to the development of hydrogen energy, and the development of proton exchange membrane hydrogen production and proton exchange membrane fuel cell technology is rapid, but the application scale is limited by the use of noble metals. The four-electron reaction rate of anode oxygen evolution in proton exchange membrane hydrogen production is slow, the overpotential is high, and the method is a main source of energy consumption. The existing catalyst mainly comprises iridium and iridium oxide, and has the disadvantages of poor intrinsic activity, small specific surface area, noble metal utilization rate and poor conductivity. Iridium is often present in an amount of 1mg/cm 2 or more, while iridium is one of the most rare elements in the crust, with annual yields of only about 3-5 tons. In order to reduce the cost and improve the energy conversion efficiency, the intrinsic activity of the catalyst is further improved, the specific surface area of the catalyst is further improved, the electrical conductivity of the catalyst is further improved, and the consumption of noble metals is further reduced. For this reason, development of iridium-based catalysts of novel composition and structure is desired. Disclosure of Invention In order to solve the technical problems, the invention aims to provide the iridium-containing catalyst and the preparation method thereof, and the iridium-containing catalyst has a one-dimensional nanowire structure and has the advantages of high specific surface area, high activity, good stability and the like. The invention also aims to provide a post-treatment method suitable for the iridium-containing catalyst, which can optimize the product components and improve the catalytic activity and stability. The invention also aims to provide application of the iridium-containing catalyst. To achieve the above object, the present invention also provides an iridium-containing catalyst comprising an alkali metal and/or alkaline earth metal and iridium, wherein the molar ratio of (alkali metal and/or alkaline earth metal) to iridium is 0.1 to 100:1, more preferably 0.1 to 5:1, still more preferably 0.15:1 to 2:1. Iridium dioxide and iridium simple substance products synthesized by the traditional Adams method, colloid method and liquid phase reduction method are particles. According to the invention, through component innovation of the iridium-based catalyst, the intrinsic catalytic activity is improved, the noble metal consumption is reduced, and the characteristics of the new component in the synthesis process, such as the dominant growth direction, are utilized to form a one-dimensional nanowire structure, so that the specific surface area of the catalyst is improved, the conductivity of the catalyst is increased, and the utilization rate of the catalyst in the membrane electrode and the galvanic pile is improved. The technical scheme of the invention can greatly improve the catalyst performance, reduce the catalyst cost and form obvious advantages compared with the prior art. According to a specific embodiment of the present invention, preferably the iridium-containing catalyst has a dominant growth crystal orientation, more preferably the iridium-containing catalyst has a growth advantage in one or a combination of more than two of the following crystal orientations (-112), (110), (101), (200), (211), (112). According to a specific embodiment of the present invention, preferably, the iridium-containing catalyst is potassium iridium and/or cesium iridium. According to a specific embodiment of the invention, preferably, the potassium iridium is K 0.25IrO2, which has a growth advantage in the (-112) crystal direction. According to a particular embodiment of the invention, preferably, the potassium in the potassium iridium catalyst is predominantly +1 valent, the oxygen is predominantly-2 valent, and the iridium valence ranges from 0 to +6, predominantly between +3 and +4 valence. According to a specific embodiment of the present invention, preferably, the cesium iridium oxide is Cs 0.25IrO2, which has growth advantage in the (-112) crystal direction. According to a specific embodiment of the present invention, preferably, the alkali metal includes one or a combination of two or more of lithium, sodium, potassium, rubidium, cesium, etc., and more preferably, the alkali metal includes potassium and/or cesium. According to a specific embodiment of the present invention, preferably, the alkaline earth metal includes one or a combination of two or more of magnesium, calcium, strontium, barium, etc., and more preferably, the alkaline earth metal include