Preparation method of electrocatalyst carrier for fuel cell

Abstract

The present invention relates to a preparation method of an electrocatalyst carrier for fuel cells. The electrocatalyst carrier is prepared from raw materials of expanded graphite with BET surface area of no less than 100m<2> / g and average pore size of no less than 10 nm through high temperature calcination, hole plugging treatment and drying treatment; and the obtained carrier has BET specific surface area of no less than 120m<2> / g and average pore size of 8-16 nm. Compared with the traditional carbon materials, the electrocatalyst carrier has larger specific surface area, is easier to capture and uniformly disperse nano Pt particles, also has high better potential stability. The Pt / C electrocatalyst prepared by using the treated worm-shape expanded graphite as carrier preparation has the advantages of multiple active sites, high activity and stability.

Description

technical field [0001] The invention relates to the technical field of materials, in particular to a treatment process of expanded graphite material and its application as a fuel cell electrocatalyst carrier. Background technique [0002] A fuel cell is a power generation device that directly converts chemical energy stored in fuel and oxidant into electrical energy. It has the advantages of low pollution, simple structure, and high energy conversion efficiency. Among them, the proton exchange membrane fuel cell has the outstanding advantages of high output efficiency and environmental friendliness, and has broad application prospects. It can start at low temperature, has no electrolyte corrosion and leakage, and is easy to operate. It has strong competitive advantages and huge potential application prospects in the fields of electric vehicles, regional power stations, spacecraft, and portable power supplies. [0003] Electrocatalyst is the key material of fuel cell, its ac...

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Problems solved by technology

However, carbon black is very easy to agglomerate, and its structure is easily destroyed during processing, which makes Pt easy to be coated, which makes the catalytic active center relatively reduced, thereby reducing the activity of the catalyst.

In addition, during the long-term operation of the fuel cell, the carbon black will be oxidized and corroded due to changes in temperature, humidity, PH value, and operating voltage, resulting in the detachment and loss of catalyst particles from the surface of the carrier, resulting in irreversible attenuation of fuel cell performance.

Third, the hydrophilicity of the surface of the carrier that undergoes electrochemical corrosion is enhanced, which destroys the mass transfer balance of the water inside the electrode, and easily causes the battery to "flood"

[0005] As we all know, strong oxidants (such as potassium dichromate, potassium permanganate, etc.), concentrated sulfuric acid and concentrated nitric acid are inserted into the lamellar structure of flaky natural graphite, and the worm-like expanded graphite obtained after rapid expansion has a specific surface area. High density, low density, many surface atomic defects, rich in oxygen-containing functional groups, etc., and the natural graphite material of its body endows it with extremely high resistance to electrochemical corrosion; however, the large gaps between graphite worms are not It is beneficial to use it as a carrier to uniformly load and disperse active metal particles

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