Preparation method of nano catalyst for low-temp. fuel cell

Abstract

The invention relates to the method for fast preparing the nano catalyst used for the fuel cell and the sensor. The active constituent (monocomponent or polycomponent) is deioxidized or oxidized uniformly (no phase splitting) only one time, adhered to the surface of the carrier by using the microwave adjust and control technique. The chemical reactions are induced and controlled by the microwave. The drying procedure and unartificial smashing procedure are completed at the same time. The invention possesses the features of the small granule of the catalyst, even distributed, high electrochemical activity. The catalyst with the capacity of the active matter more than 40% can be prepared once by the single kettle.

Description

technical field [0001] The invention relates to a rapid preparation method of nanometer catalysts used in fuel cells and sensors. Background technique [0002] Catalysts for low-temperature fuel cells are generally supported nanomaterials, that is, catalysts with a particle size of several nanometers to tens of nanometers are supported on the surface of a conductive substrate. For example, Pt / C catalysts are platinum nanoparticles supported on the surface of activated carbon. Low-temperature fuel cells refer to fuel cells with a general operating temperature below 200°C, including proton exchange membrane fuel cells, phosphoric acid fuel cells, and direct methanol fuel cells. These fuel cells basically use the same type of nano-catalyst. Catalyst is the key material of fuel cell, and it is also a kind of material that accounts for a relatively high cost of fuel cell. Dispersing the catalyst into nanoparticles can not only make full use of the...

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Problems solved by technology

As a result, the specific surface area is greatly reduced, thereby reducing the electrochemical activity of the catalyst

Another disadvantage of these methods is that the preparation time is very long. For example, the method disclosed in patent CN 1330424A needs 8-30 hours for chemical reduction at 80° C., plus carrier pretreatment, mixing, drying and pulverization, it takes about one to three hours. two days

Another problem with these methods is that when preparing multi-component catalyst systems, it is easy to cause phase separation of multiple components

Because the precursors of different catalyst materials have different solubility products in the existing solution, during the drying process, the salt with a small solubility product precipitates first, and the salt with a large solubility product precipitates later, and finally a uniform alloy cannot be formed

Therefore, for the preparation of multi-component catalysts, the method of freeze-drying is usually adopted, but the speed of freeze-drying is very slow, and generally needs more than 6 hours

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