Method of surface nano-crystallization of noble metal catalyst

A noble metal catalyst, nanotechnology, applied in the direction of catalyst activation/preparation, metal/metal oxide/metal hydroxide catalyst, chemical instruments and methods, etc., can solve the problems of fragility and limited application, and achieve high mechanical strength , high specific surface area, performance improvement effect

Inactive Publication Date: 2009-01-07
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, studies have shown that although nanoporous metals prepared by dealloying exhibit good structural continuity microscopically, they appear as a fragile material macroscopically because their structural units are at the nanoscale. Thus limiting its application in certain fields such as

Method used

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  • Method of surface nano-crystallization of noble metal catalyst
  • Method of surface nano-crystallization of noble metal catalyst
  • Method of surface nano-crystallization of noble metal catalyst

Examples

Experimental program
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Embodiment 1

[0045] 1) Anneal a platinum wire with a length of 3 cm and a diameter of 0.1 mm at 500 ° C for 16 h, soak it in 68 wt.% nitric acid for 2 h, clean it with ultrapure water, and 2 SO 4 In the process, the reversible hydrogen electrode was used as the reference electrode, and the cyclic voltammetry curve was scanned between 0-1.5V.

[0046] 2) CuSO at 0.1mol / L 4 In the solution, the mercurous mercurous sulfate electrode is used as the reference electrode, and the cyclic voltammetry curve is scanned between -0.45-0.8V (such as figure 1 ), and then deposited copper at a constant potential of -0.4V for 10000s.

[0047] 3) The copper-deposited platinum wire was annealed at 700° C. for 3 h under the protection of hydrogen.

[0048] 4) The sample after annealing was heated at 0.5mol / L H 2 SO 4 In this method, the reversible hydrogen electrode was used as the reference electrode, and the electrolytic corrosion was performed at a potential of 1.3V for 10000s to prepare a platinum wi...

Embodiment 2

[0050] 1) Anneal a gold wire with a length of 3 cm and a diameter of 0.1 mm at 500 ° C for 16 h, soak it in 60 wt.% nitric acid for 2 h, clean it with ultrapure water, and 2 SO 4 In the process, the reversible hydrogen electrode was used as the reference electrode, and the cyclic voltammetry curve was scanned between 0-1.8V.

[0051] 2) CuSO at 0.1mol / L 4 In the solution, the mercury mercurous sulfate electrode was used as the reference electrode, and the cyclic voltammetry curve was scanned between -0.45-1.1V, and then copper was deposited at the constant potential of -0.45V for 10000s.

[0052] 3) The copper-deposited gold wire was annealed at 700° C. for 3 h under the protection of hydrogen.

[0053] 4) The sample after annealing was heated at 0.5mol / L H 2 SO 4 In this method, using a reversible hydrogen electrode as a reference electrode, electrolytically corroded for 10,000 s at a potential of 1.4V, a gold wire with a nanoporous surface was prepared. Its in 0.5mol / L ...

Embodiment 3

[0055] 1) Platinum mesh with a length of 1 cm and a width of 0.5 cm (such as Figure 8 shown) annealed at 500°C for 16h, soaked in 70wt.% nitric acid for 2h, cleaned with ultrapure water, and then heated at 0.5mol / LH 2 SO 4 In the process, the reversible hydrogen electrode was used as the reference electrode, and the cyclic voltammetry curve was scanned between 0-1.5V.

[0056] 2) CuSO at 0.1mol / L 4 In the solution, the mercurous mercurous sulfate electrode is used as the reference electrode, and the cyclic voltammetry curve is scanned between -0.45-0.8V, and then the copper is deposited at the constant potential of -0.45V for 22000s (such as Figure 9 shown).

[0057] 3) The copper-deposited platinum mesh was annealed at 700° C. for 3 h under the protection of hydrogen.

[0058] 4) The sample after annealing was heated at 0.5mol / L H 2 SO 4 In this method, the reversible hydrogen electrode was used as a reference electrode, and electrolytic corrosion was performed at a p...

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Abstract

The invention discloses a method used for improving the surface nano-modification of a noble metal catalyst, and the method comprises the following steps: a relatively active metal (such as copper, silver, nickel, aluminium, etc.) with a certain thickness is deposited on the surface of a platinum wire (or a platinum net, a platinum sheet, a gold wire, a gold plaque, a palladium wire, or the alloy thereof) through the chemical deposition method or the electrochemical deposition method, and annealed under the protection of reducing atmosphere, so an alloy with a certain thickness is formed by the mutual diffusion of the active metal and platinum (or gold, palladium, etc., or other alloys); under proper conditions, the active metal in the alloy and the outside active metal which is not changed into the alloy are corroded, thereby forming a porous surface structure. The method of the invention utilizes and controls the alloying process and the dealloying process to improve the surface nano-modification of the noble metal catalyst material, thereby possessing higher specific surface area, and simultaneously having higher mechanical strength and higher catalytic activity.

Description

technical field [0001] The present invention relates to a method for improving the performance of noble metal catalysts, in particular to a process of controlling the alloying and dealloying to modify the surface of macroscale noble metal catalyst materials to have a higher specific surface area, At the same time, it has a high mechanical strength processing method. Background technique [0002] As we all know, precious metal materials such as platinum and palladium are important industrial catalysts, and are widely used in many fields such as cathode or anode of fuel cells, catalytic hydrogenation and oxidation of olefins, and automobile exhaust gas treatment. However, due to its high price, most of the noble metal catalysts used in industry are to support noble metal nanoparticles on carbon powder, metal oxide nanoparticles or porous molecular sieves to improve the utilization efficiency of platinum. However, the preparation method of the supported nanoparticle catalyst p...

Claims

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Application Information

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IPC IPC(8): B01J37/34B01J23/89B01J35/10
Inventor 丁轶王荣跃
Owner SHANDONG UNIV
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