Cerium oxide-coated precious metal nano-catalyst and preparation method thereof

A nano-catalyst and noble metal technology, applied in the field of noble metal catalyst preparation, can solve the problems of poor thermal stability and anti-poisoning ability, achieve excellent anti-sintering performance, reduce costs, and simplify the preparation steps

Active Publication Date: 2015-11-25
吉林晟航科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this type of preparation method can obtain a catalyst with high catalytic activity, it often shows poor thermal stability and anti-poisoning ability due to the lack of effective protection of the noble metal surface.

Method used

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  • Cerium oxide-coated precious metal nano-catalyst and preparation method thereof
  • Cerium oxide-coated precious metal nano-catalyst and preparation method thereof
  • Cerium oxide-coated precious metal nano-catalyst and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0038] This embodiment provides a catalyst PdCeO coated with palladium in cerium oxide 2 , which is prepared by the following steps:

[0039] Dissolve 0.15g sodium bromide in 100mL water, add 0.6g cerium nitrate, stir and mix well, then add 0.25mmol Na 2 PdCl 4 , to obtain a mixed solution;

[0040] The temperature of the mixed solution was raised and stabilized at 60 ° C, and 0.25 mL of ammonia water (concentration: 25 wt %) was added, kept for 1 h and then cooled to room temperature;

[0041] Add 400mL of acetone and carry out centrifugation, then wash the separated product three times to obtain the catalyst PdCeO coated with cerium oxide palladium 2 , which contains palladium 11wt.%, cerium oxide 89wt.%.

[0042] figure 1 for PdCeO 2 The XRD pattern of figure 1 It can be seen that the PdCeO 2 It is composed of pure cerium oxide and palladium. figure 2 for PdCeO 2 The TEM image of figure 2 It can be seen that the PdCeO 2With a core-shell structure, cerium oxide...

Embodiment 2

[0048] This embodiment provides a cerium oxide-coated gold catalyst AuCeO 2 , which is prepared by the following steps:

[0049] Dissolve 0.15g of sodium chloride in 100mL of water, add 0.6g of cerium nitrate, stir and mix evenly, then add 0.25mmol of chloroauric acid to obtain a mixed solution;

[0050] The temperature of the mixed solution was raised and stabilized at 60 °C, and 0.25 mL of ammonia water (concentration: 25 wt.%) was added, kept for 1 h and then cooled to room temperature;

[0051] Add 400mL of acetone and carry out centrifugation, then wash the separated product three times with water to obtain the catalyst AuCeO coated with cerium oxide. 2 .

[0052] Figure 5A and Figure 5B AuCeO prepared for this example 2 The TEM image of Figure 5A and Figure 5B It can be seen that the catalyst AuCeO 2 It maintains a good core-shell structure, which contains 14wt.% of gold and 86wt.% of cerium oxide. The obtained product is a core-shell structure of ceria-coat...

Embodiment 3

[0054] This embodiment provides a catalyst PtCeO coated with platinum in cerium oxide 2 , which is prepared by the following steps:

[0055] Dissolve 0.15g of potassium iodide in 100mL of water, add 0.6g of cerium nitrate, stir and mix evenly, then add 0.25mmol of chloroplatinic acid to obtain a mixed solution;

[0056] The temperature of the mixed solution was raised and stabilized at 60 °C, and 0.25 mL of ammonia water (concentration: 25 wt.%) was added, kept for 1 h and then cooled to room temperature;

[0057] Add 400mL acetone and carry out centrifugation, then wash the separated product three times with water to obtain the catalyst PtCeO coated with cerium oxide platinum. 2 , which contains 21wt.% of platinum and 79wt.% of cerium oxide, and the obtained product has a core-shell structure of cerium oxide covering platinum.

[0058] Figure 6 The PtCeO prepared for this example 2 The TEM image of Figure 6 In A to C and D to F, the consumption of potassium iodide is i...

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Abstract

The invention provides a cerium oxide-coated precious metal nano-catalyst and its preparation method. The method comprises the following steps: mixing a halogen-containing compound and water, adding cerous salt, stirring, and adding a precious metal precursor to obtain a mixed solution; and heating the mixed solution to 30-90 DEG C, adding ammonia water, carrying out thermal insulation at 30-90 DEG C for 0.5-4 h, cooling to room temperature, carrying out centrifugal separation, and washing to obtain the cerium oxide-coated precious metal nano-catalyst. The invention also provides a cerium oxide-coated precious metal nano-catalyst prepared by the above method. During the reaction process of the preparation method, no organic component is added, and no surface modification is required. Thus, costs are reduced, steps are simplified, and nontoxic and low-energy mass production is realized. The core-shell structure of the above catalyst has excellent sintering resistance. The catalyst has high catalytic activity and has high thermal stability.

Description

technical field [0001] The invention relates to a noble metal nano catalyst coated with cerium oxide and a preparation method thereof, belonging to the technical field of preparation of noble metal catalysts. Background technique [0002] At present, the preparation of most noble metal catalysts is based on a simple surface loading process, that is, directly depositing or coating noble metal precursors on the substrate surface, and then preparing supported noble metal nanocatalysts by low-temperature reduction or high-temperature sintering. Although this type of preparation method can obtain catalysts with high catalytic activity, it often shows poor thermal stability and anti-poisoning ability due to the lack of effective protection of the noble metal surface. [0003] Generally speaking, as the working temperature increases, the noble metal nanoparticles as the catalytic active center will irreversibly agglomerate or re-grow, thus deactivation occurs. [0004] Therefore, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63
Inventor 张洪杰汪啸刘大鹏
Owner 吉林晟航科技发展有限公司
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