Gold-platinum nanocomposite material and its preparation method and its application in direct methanol fuel cell anode catalyst

Abstract

The invention discloses a composite nano gold-platinum material. Nano gold is in a dendritic shape, spherical platinum particles are modified on the surface of the nano gold, a molar ratio of gold to platinum is 16: (4 to 5), the size of the nano gold is 0.1 to 7 micrometers, and the size of each platinum particle is 1.5 to 4 nanometers. The preparation method comprises the following two steps: step 1, electrically depositing an electrolyte solution containing chloroauric acid in a three-electrode system at a constant potential to obtain a nano gold modified electrode; and step 2, inserting the nano gold modified electrode into a reducing agent solution containing potassium chloroplatinite, carrying out the chemical reduction deposition, and depositing the platinum particles on the surface of the nano gold modified electrode to obtain the composite nano gold-platinum material. The composite nano gold-platinum material has high toxicity resistance and relatively high corrosion resistance to a reaction intermediate product CO; and after Au and Pt are composited, the internal atomic arrangement and the Fermi level of Pt can be changed, so that the surface performance of Pt is changed, and the surface catalytic activity, toxicity resistance and stability of the composite material are improved.

Description

technical field [0001] The invention relates to fuel cell catalyst technology, in particular to a preparation method and application of a gold-platinum nanocomposite material. Background technique [0002] Fuel cells are devices that directly and continuously convert chemical energy into electrical energy. Because of their high efficiency, reliability, and cleanliness, they have attracted extensive attention and are widely used in many fields such as power stations and power sources. However, the use of small organic molecules such as hydrogen and methane as fuel in fuel cells has problems such as hydrogen source problems, safety problems, air pollution, and short operating life. In order to solve the above problems, it is obviously more feasible to use liquid fuel instead of hydrogen as fuel. Among liquid small molecules, methanol has high solubility in electrolyte solution, and it has abundant sources, low price and easy storage. Therefore, the direct methanol fuel cell ...

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Problems solved by technology

However, the preparation of nanomaterials by chemical reduction method is difficult to control the particle size and distribution of the product, and the prepared catalyst has weak adhesion and poor stability on electrodes or devices.

In the process of direct electrochemical deposition of Pt, the deposition efficiency of Pt will be reduced due to the hydrogen evolution effect; in this process, the current and voltage may be unstable, which will also lead to the inhomogeneity of the prepared Pt nanoparticles, thereby affecting its performance; in addition Due to the existence of nucleation overvoltage and concentration diffusion, the "Matthew effect" of grain growth in the electrodeposition process is formed, resulting in coarse deposited Pt grains

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