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CN-118949980-B - High-activity Pt/GaCe-Al2O3Catalyst, preparation method and application thereof

CN118949980BCN 118949980 BCN118949980 BCN 118949980BCN-118949980-B

Abstract

The invention discloses a high-activity Pt/GaCe-Al 2 O 3 catalyst and a preparation method and application thereof, wherein Ga and Ce doped Al 2 O 3 carrier is synthesized by a hydrothermal synthesis method, and metal Pt is loaded on the synthesized GaCe-Al 2 O 3 carrier by an impregnation method to obtain the high-dehydrogenation-activity Pt/GaCe-Al 2 O 3 catalyst. The catalyst has a nano sheet structure and has strong adsorption performance on methylcyclohexane, and the methylcyclohexane dehydrogenation reaction shows excellent catalytic dehydrogenation activity and stability under the conditions of 300 ℃ and normal pressure, so that the ultrahigh hydrogen release rate can be realized.

Inventors

  • CAO JINGPEI
  • CHEN CHENXU
  • Yao Naiyu
  • JIANG WEI
  • ZHANG CHUANG
  • Huan Zuxing
  • HU XIN

Assignees

  • 中国矿业大学

Dates

Publication Date
20260508
Application Date
20240828

Claims (8)

  1. 1. The application of the high-activity Pt/GaCe-Al 2 O 3 catalyst in catalyzing the dehydrogenation of methylcyclohexane is characterized in that the high-activity Pt/GaCe-Al 2 O 3 catalyst is prepared by the following steps: (1) Mixing aluminum salt, urea, cerium salt and gallium salt in water, placing the obtained mixture in an autoclave for hydrothermal reaction, cooling to room temperature, washing, drying and calcining the precipitate to obtain GaCe-Al 2 O 3 carrier; (2) Adding GaCe-Al 2 O 3 carrier prepared in the step (1) into an impregnating solution containing a platinum precursor, carrying out ultrasonic mixing, then carrying out vacuum impregnation for 12 hours, drying after the impregnation is finished, and calcining in an inert atmosphere to obtain the Pt/GaCe-Al 2 O 3 catalyst.
  2. 2. The use according to claim 1, wherein the hydrothermal reaction in step (1) is carried out at a temperature of 100 o C for a period of 48 hours.
  3. 3. The use according to claim 1, wherein the drying in step (1) is at a temperature of 100 o C for a period of 12 hours, and the calcination is at a temperature of 750 ℃ for a period of 2 hours.
  4. 4. The use according to claim 1, wherein in step (1) the aluminium salt is aluminium nitrate, the cerium salt is cerium nitrate and the gallium salt is gallium nitrate.
  5. 5. The use of claim 1, wherein the platinum precursor in step (2) is chloroplatinic acid and the impregnating solution is one of deionized water, ethanol, and acetone.
  6. 6. The use according to claim 1, wherein the calcination in step (2) is carried out at a temperature of 500 o C for a period of 2h.
  7. 7. The use according to claim 1, characterized in that the loading of Pt in the highly active Pt/GaCe-Al 2 O 3 catalyst is 0.5wt.%, the addition of Ga is 1.5wt.%, and the addition of Ce is 1.5wt.%.
  8. 8. The use according to claim 1, wherein the specific application step comprises: Adding catalyst particles with the particle size of 40-60 meshes diluted by quartz sand into a reaction tube, then keeping the temperature at 300 o ℃ and the pressure at 0.1 MPa, controlling the flow rate of methylcyclohexane to be 30L/min and gasifying the methylcyclohexane under the condition of 180 o ℃, adjusting the flow rate of carrier gas to be 10-50mL/min, and pumping the mixed gas of methylcyclohexane and carrier gas into the reactor together to obtain toluene and hydrogen.

Description

High-activity Pt/GaCe-Al 2O3 catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of catalyst preparation, in particular to a high-activity Pt/GaCe-Al 2O3 catalyst, and a preparation method and application thereof. Background The liquid organic hydrogen storage is based on the reversible reaction of organic hydride hydrogenation and dehydrogenation to store hydrogen, has the characteristics of higher hydrogen storage density, high reversibility of hydrogenation-dehydrogenation and the like, is very compatible with the existing energy infrastructure, and does not need a great deal of capital investment. Liquid organic hydrogen storage is therefore considered an attractive method of hydrogen storage. Methylcyclohexane (MCH) is considered an ideal liquid hydrogen storage material due to its low toxicity, high reversibility of hydrogen circulation, and theoretical hydrogen storage capacity (6.1 wt.%). Methylcyclohexane dehydrogenation is a strong endothermic reaction and generally requires higher reaction temperatures to achieve efficient hydrogen release rates, and also results in short catalyst life. Therefore, it is important to develop a catalyst with high hydrogen release rate and good stability, and to realize convenient hydrogen utilization. In the preparation of the catalyst, pt metal has stronger C-H bond activation capability and lower C-C bond cracking capability, and is widely applied to catalytic dehydrogenation. Besides the active metal, the carrier is also an important component, and the gamma-Al 2O3 can effectively improve the interaction of the metal carrier, enhance the dispersion of the active ingredient and maintain the unique properties of the impregnated metal due to the good mechanical and chemical properties of the gamma-Al 2O3. Therefore, pt/Al 2O3 catalyst is the most commonly used dehydrogenation catalyst, but the catalytic dehydrogenation activity of the catalyst is not high, and the catalyst is easy to deactivate, so that the purity of the product hydrogen is low. Disclosure of Invention One of the purposes of the invention is to provide a preparation method of a high-activity Pt/GaCe-Al 2O3 catalyst, and the dehydrogenation rate and stability of the monometal Pt/Al 2O3 catalyst are enhanced by aid metal. The second purpose of the invention is to provide the high-activity Pt/GaCe-Al 2O3 catalyst prepared by the preparation method. It is a further object of the present invention to provide the use of the highly active Pt/GaCe-Al 2O3 catalyst described above for catalytic dehydrogenation. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: In one aspect of the invention, a method for preparing a high-activity Pt/GaCe-Al 2O3 catalyst is provided, which comprises the following steps: (1) Mixing aluminum salt, urea, cerium salt and gallium salt in water, placing the obtained mixture in an autoclave for hydrothermal reaction, cooling to room temperature, washing, drying and calcining the precipitate to obtain GaCe-Al 2O3 carrier; (2) Adding GaCe-Al 2O3 carrier prepared in the step (1) into an impregnating solution containing a platinum precursor, carrying out ultrasonic mixing, then carrying out vacuum impregnation for 12 hours, drying after the impregnation is finished, and calcining in an inert atmosphere to obtain the Pt/GaCe-Al 2O3 catalyst. Preferably, the temperature of the hydrothermal reaction in step (1) is 100 ℃ and the time is 48 hours. Preferably, the drying temperature in the step (1) is 100 ℃ and the time is 12 hours, and the calcining temperature is 750 ℃ and the time is 2 hours. Preferably, in the step (1), the aluminum salt is aluminum nitrate, the cerium salt is cerium nitrate, and the gallium salt is gallium nitrate. Preferably, the impregnating solution in step (2) is one of deionized water, ethanol and acetone. Preferably, the calcination in step (2) is carried out at a temperature of 500 ℃ for a period of 2 hours. Preferably, the platinum precursor in step (2) is chloroplatinic acid. In another aspect of the invention, a high activity Pt/GaCe-Al 2O3 catalyst is provided, and the catalyst is prepared by the preparation method. Preferably, the loading of Pt in the catalyst is 0.5wt.%, the addition amount of Ga is 1.5wt.%, and the addition amount of Ce is 1.5wt.%. The catalyst is of a nano sheet structure and has stronger adsorption performance on methylcyclohexane. In another aspect, the invention also provides the application of the high-activity Pt/GaCe-Al 2O3 catalyst in catalyzing MCH dehydrogenation. The specific application steps comprise tabletting, crushing and sieving the catalyst to obtain catalyst particles with the particle size of 40-60 meshes. 50mg of catalyst diluted with quartz sand (total: 0.55 g) was added to the reaction tube (inner diameter=8mm), and then the temperature was maintained at 300℃and the pressure was maintained at 0.1MPa. The