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CN-121988346-A - Platinum-iron-molybdenum catalyst with high activity and stability, and preparation method and application thereof

CN121988346ACN 121988346 ACN121988346 ACN 121988346ACN-121988346-A

Abstract

The invention discloses a platinum-iron-molybdenum catalyst with high activity and stability, and a preparation method and application thereof, and belongs to the technical field of heterogeneous catalysis. The method comprises the steps of dissolving ferric nitrate, ammonium molybdate and citric acid in water, mixing, regulating the pH value to be lower than 1.0, carrying out water bath gelation and drying on the solution, calcining in a tube furnace to obtain a ferric molybdate carrier, mixing a platinum source with the ferric molybdate carrier, evaporating the mixture in an oil bath, drying, and calcining in a muffle furnace to obtain the platinum-iron-molybdenum catalyst. The platinum-iron-molybdenum catalyst prepared by the invention can show high-efficiency catalytic activity and excellent stability in the reaction of propane oxidation no matter the platinum cluster prepared in advance is loaded or the precursor salt of platinum is directly wet-impregnated.

Inventors

  • TAN WEI
  • FANG YU
  • YANG JIAWEI
  • YANG YIRUI
  • DONG LIN

Assignees

  • 南京大学

Dates

Publication Date
20260508
Application Date
20260130

Claims (10)

  1. 1. A preparation method of a platinum-iron-molybdenum catalyst with high activity and stability is characterized by dissolving ferric nitrate, ammonium molybdate and citric acid in water, mixing, adjusting the pH value to be lower than 1.0, gelling and drying the solution in a water bath, calcining in a tube furnace to obtain a siderophore, mixing a platinum source with the siderophore, evaporating to dryness in an oil bath, drying, and calcining in a muffle furnace to obtain the platinum-iron-molybdenum catalyst.
  2. 2. The method for preparing a platinum-iron-molybdenum catalyst with high activity and stability according to claim 1, wherein the Pt loading amount in the platinum source is 0.5-1 wt%.
  3. 3. The method for preparing a platinum-iron-molybdenum catalyst with high activity and stability according to claim 1, wherein the platinum source is supported by one of a glycol reduction method, a wet impregnation method, an incipient wetness impregnation method, a deposition-precipitation method, a sol-gel method and a reduction deposition method.
  4. 4. The preparation method of the platinum-iron-molybdenum catalyst with high activity and stability according to claim 1, wherein the calcination temperature of the tube furnace is 450 ℃, the time is 2h ℃ and the heating rate is 2 ℃ per minute, the calcination temperature of the muffle furnace is 400 ℃, the calcination time is 2h and the heating rate is 5 ℃ per minute.
  5. 5. The method for preparing a platinum-iron-molybdenum catalyst with high activity and stability according to claim 1, wherein the drying temperature is 60-120 ℃.
  6. 6. The method for preparing the platinum-iron-molybdenum catalyst with high activity and stability according to claim 1, wherein the total molar ratio of citric acid to metal ions in ferric nitrate and ammonium molybdate is 1:3.
  7. 7. The platinum-iron-molybdenum catalyst with high activity and stability prepared by the preparation method of the platinum-iron-molybdenum catalyst with high activity and stability according to any one of claims 1-6.
  8. 8. Use of the platinum iron molybdenum catalyst according to claim 7 in a propane oxidation reaction.
  9. 9. The method for preparing the platinum iron molybdenum catalyst for the oxidation reaction of propane, according to claim 8, wherein the catalytic condition of the oxidation reaction of propane is that the catalyst particle size is 40-60 meshes, the reaction condition is 4000 ppm C 3 H 8 and 5% O 2 , and the tested mass space velocity is 100000 mL.g cat -1 ·h -1 .
  10. 10. The method according to claim 9, wherein the catalytic reaction temperature is 50-400 ℃.

Description

Platinum-iron-molybdenum catalyst with high activity and stability, and preparation method and application thereof Technical Field The invention belongs to the technical field of heterogeneous catalysis, and particularly relates to a platinum-iron-molybdenum catalyst with high activity and stability, and a preparation method and application thereof. Background The high emission of Volatile Organic Compounds (VOCs) is regarded as a hazardous atmospheric pollutant, which has resulted in serious environmental problems. Among these volatile organic compounds, the chemically stable light alkanes are the most difficult ones to eliminate. Liquefied petroleum gas, a mixture of light alkanes (propane and butane), has been widely used as a major gasoline substitute for automobiles. During cold start-up, the catalytic converter is not effective in oxidizing light alkanes and CO to harmless carbon dioxide and water. Therefore, developing a low temperature alkane oxidation catalyst is a promising method for removing light alkanes in automobile exhaust. Conventional alkane oxidation catalysts are mainly classified into noble metal groups (such as Pt, pd, au) and non-noble metal groups (such as transition metal oxides of Mn, co, etc.). The noble metal catalyst (particularly Pt-based catalyst) has excellent electron transfer capability and surface adsorption activation performance, so that the light alkane can be efficiently activated under the low-temperature condition, and the catalyst has higher catalytic activity. However, the catalyst is faced with two bottleneck problems, namely, the economic cost is too high, the universality of application is not strong, and the catalytic activity cannot be further broken through at low temperature, and the stability and the resistance are poor. The existing catalyst system generally has the problem of insufficient low-temperature activity, so that the reaction needs to be operated at a higher temperature, and the energy consumption and the cost are high. Meanwhile, the high-performance catalytic material depends on noble metals such as platinum, palladium and the like, the high price and the resource scarcity severely restrict the large-scale economical application of the technology, and the material is extremely sensitive to sulfur, chlorine and other impurities in complex industrial atmosphere and is easy to generate irreversible poisoning and deactivation. The long-term stability of the catalyst is also not ideal, and particularly sintering, phase change or loss of active components easily occurs in a high-temperature environment containing water vapor, resulting in shortened life. In order to break through the bottlenecks and further improve the low-temperature activity of the propane combustion catalyst, moO 3 is introduced into the traditional Pt-based catalyst, and can provide an acidic site to adsorb and activate propane, which is a method for improving the activity of the catalyst commonly used at present, but suffers from poor long-term stability, and the activity is easily influenced by impurities such as sulfur, water and the like in the atmosphere. By introducing low-cost iron element, the long-term stability of the catalyst and the water resistance and sulfur resistance of the catalyst are improved. One current method for preparing iron-molybdenum-based catalysts is a plasma arc method, which comprises the steps of inputting a catalyst precursor which is easy to decompose and a sulfur auxiliary agent into a plasma arc device, and then preparing the sulfur-modified iron-molybdenum-based catalyst under the action of hydrogen and a plasma arc. Chinese patent publication No. CN119056462a discloses the preparation of iron-molybdenum based composite oxide catalysts using this method. However, the method has the defects of high precursor cost, poor stability, difficult precise regulation and control of reaction temperature and sulfur doping uniformity, insufficient dispersibility of active sites of products, prominent equipment energy consumption, safety, environmental protection risk and the like in the industrial amplification process. Thus, there is a need in the art to develop a platinum iron molybdenum catalyst for low temperature alkane oxidation. Disclosure of Invention The first technical problem to be solved by the invention is to provide a platinum-iron-molybdenum catalyst with high activity and stability, which has both high activity and high stability, the second technical problem to be solved by the invention is to provide a preparation method of the platinum-iron-molybdenum catalyst with high activity and stability, which has simple and convenient preparation process and practical application prospect, and the third technical problem to be solved by the invention is to provide the application of the catalyst in propane oxidation reaction. In order to solve the technical problems, the invention adopts the following technical scheme: A process for preparing the