Preparation method of high hydrophobic carbon paper

Abstract

This invention provides a method for preparing highly hydrophobic carbon paper, belonging to the field of fuel cell technology. The method includes the following steps: Step 1, impregnating carbon paper in a mixed aqueous solution of transition metal organosalt and polymer; Step 2, drying the impregnated carbon paper and then spreading it evenly on nitrogen-containing organic powder, treating it in an inert atmosphere at a certain temperature range for a period of time to obtain a highly hydrophobic carbon paper. The fiber surface of the prepared carbon paper is covered with carbon nanotube arrays, and the water contact angle is greater than 145°. This invention significantly improves the hydrophobicity of carbon paper while also maintaining excellent electrical conductivity, and the process is simple, significantly improving fuel cell performance.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, and specifically relates to a method for preparing highly hydrophobic carbon paper. Background Technology

[0002] Carbon paper is a core material of the membrane electrode assembly (MEA) in fuel cells. As a supporting material for the gas diffusion layer in fuel cells, it can support the catalyst layer and provide electron channels, heat transfer channels, gas channels and drainage channels for electrode reactions.

[0003] High hydrophobicity is a crucial requirement for carbon paper. Unmodified carbon paper is prone to flooding and cannot meet the requirements of fuel cells. Post-treatment with surface modification for hydrophobicity is essential. Common methods involve coating the carbon paper surface with chemicals such as fluorides and silanes, but these methods often suffer from uneven coating and reduced conductivity. Research indicates that surface microstructuring is also an important means of constructing hydrophobic interfaces. Constructing uniformly distributed carbon nanotubes on the fiber surface using vapor-phase growth technology is a feasible approach.

[0004] In summary, to avoid problems such as uneven coating and reduced conductivity associated with traditional hydrophobic processes, developing novel surface hydrophobic modification processes is an urgent issue to be addressed. Summary of the Invention

[0005] Based on this, the present invention provides a method for preparing highly hydrophobic carbon paper. By impregnating carbon paper with a transition metal organosalt and a polymer solution, and then heat-treating it in a nitrogen-containing organic powder, highly hydrophobic carbon paper with a carbon nanotube array grown on its surface is successfully prepared, achieving not only excellent hydrophobicity but also high electrical conductivity.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] A method for preparing highly hydrophobic carbon paper includes the following steps: S1, immersing carbon paper in a mixed aqueous solution of transition metal organosalt and polymer; S2, drying the immersed carbon paper and spreading it evenly on nitrogen-containing organic powder, and heating it to a certain temperature range in an inert atmosphere for a period of time to obtain a highly hydrophobic carbon paper.

[0008] In the above-mentioned method for preparing highly hydrophobic carbon, in step S1, the water-soluble polymer is one or more of polyethylene oxide, polyacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose, carboxyethyl cellulose, and sodium alginate.

[0009] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S1, the transition metal organosalt is one or two of ferrocene, iron acetylacetone, cobalt acetylacetone, nickel acetylacetone, cobalt naphthenate, nickel citrate, iron citrate, iron stearate, and cobalt stearate.

[0010] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S1, the concentration of the transition metal organic salt is 0.5 mol / L-3 mol / L.

[0011] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S1, the polymer is one of polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, and polylactic acid.

[0012] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S2, the nitrogen-containing organic compound is one of melamine, urea, ethylenediamine, isocyanate, and aspartic acid.

[0013] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S2, the mass ratio of gaseous nitrogen-containing organic matter to carbon paper is 2:1-10:1.

[0014] In the above-mentioned method for preparing highly hydrophobic carbon paper, in step S2, the heat treatment temperature is 600℃-1000℃ and the treatment time is 30min-3h.

[0015] Furthermore, the carbon fiber surface of the prepared carbon paper is covered with an array of carbon tubes, and the water contact angle is greater than 135°.

[0016] Compared with the prior art, the method for preparing carbon paper of the present invention has the following beneficial effects:

[0017] 1) This preparation method significantly improves the hydrophobicity of carbon paper by growing carbon nanotube arrays on the surface of carbon paper, and the water contact angle can reach more than 145°.

[0018] 2) The carbon paper prepared by this method avoids the problem of decreased electrical conductivity that occurs in traditional processes.

[0019] 3) The preparation method is simple and controllable. By adjusting parameters such as impregnating agent concentration and chemical vapor deposition time, the length density of carbon nanotube arrays can be controlled, thereby controlling the hydrophobicity. Detailed Implementation

[0020] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0021] Example 1

[0022] Carbon paper was impregnated in a 1.5 mol / L aqueous solution of cobalt acetylacetonate and polyacrylic acid (PAA), with a PAA mass concentration of 1.5%. The impregnation time was 40 minutes to ensure sufficient absorption of the solution by the carbon paper. The impregnated carbon paper was dried to 70°C and then spread evenly on melamine powder at a melamine-to-carbon paper mass ratio of 4:1. It was then heated to 600°C in an inert atmosphere for 2 hours to form a uniform array of carbon nanotubes on the surface of the carbon paper. The final carbon paper had a water contact angle of 145°.

[0023] Example 2

[0024] Carbon paper was impregnated in a 0.8 mol / L aqueous solution of ferrocene and polyethylene oxide (PEO), with a PEO concentration of 3%. The impregnation time was 20 minutes to ensure sufficient absorption of the solution by the carbon paper. The impregnated carbon paper was then dried to 80°C and spread evenly on urea powder at a urea-to-carbon paper mass ratio of 2:1. It was then heated to 750°C in an inert atmosphere for 0.5 hours to form a uniform array of carbon nanotubes on the carbon paper surface. The final carbon paper exhibited a water contact angle of 147°.

[0025] Example 3

[0026] Carbon paper was impregnated in a 0.5 mol / L aqueous solution of ferric citrate and polyacrylic acid (PAA), with a PAA mass concentration of 1.5%. The impregnation time was 40 minutes to ensure sufficient absorption of the solution by the carbon paper. The impregnated carbon paper was dried to 70°C and then spread evenly on ethylenediamine powder at a mass ratio of ethylenediamine to carbon paper of 4:1. It was then heated to 850°C in an inert atmosphere for 3 hours to form a uniform array of carbon nanotubes on the surface of the carbon paper. The final carbon paper had a water contact angle of 146°.

[0027] Example 4

[0028] Carbon paper was impregnated in a 3 mol / L aqueous solution of cobalt naphthenate and polyvinylpyrrolidone (PVP), with a PVP concentration of 4%. The impregnation time was 1 hour to ensure sufficient absorption of the solution by the carbon paper. The impregnated carbon paper was then dried to 90°C and spread evenly on isocyanate powder at a mass ratio of isocyanate to carbon paper of 10:1. It was then heated to 1000°C in an inert atmosphere for 1 hour to form a uniform array of carbon nanotubes on the surface of the carbon paper. The final carbon paper had a water contact angle of 150°.

[0029] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for preparing highly hydrophobic carbon paper, characterized in that, Includes the following steps: Step 1: Immerse the carbon paper in a mixed aqueous solution of transition metal organosalt and polymer; Step 2: After drying the impregnated carbon paper, spread it evenly on nitrogen-containing organic powder and heat it in an inert atmosphere to a certain temperature range for a period of time to obtain a highly hydrophobic carbon paper.

2. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The transition metal organosalt mentioned in step 1 is one or two of ferrocene, iron acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, cobalt naphthenate, nickel citrate, iron citrate, iron stearate, and cobalt stearate.

3. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The concentration of the transition metal organic salt mentioned in step 1 is 0.5 mol / L-3 mol / L.

4. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The polymer mentioned in step 1 is one of polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, and polylactic acid.

5. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The nitrogen-containing organic compound mentioned in step 2 is one of melamine, urea, ethylenediamine, isocyanate, and aspartic acid.

6. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The mass ratio of nitrogen-containing organic matter to carbon paper in step 2 is 2:1 to 10:

1.

7. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The heat treatment temperature in step 2 is 600℃-1000℃, and the treatment time is 30min-3h.

8. The method for preparing highly hydrophobic carbon paper according to claim 1, characterized in that, The carbon paper fiber surface is covered with an array of carbon tubes, and the water contact angle is greater than 145°.