KR-20260063025-A - MANUFACTURING METHOD OF CARBON SUPPORT WITH IMPROVED POROSITY AND SURFACE HYDROPHOBICITY

KR20260063025AKR 20260063025 AKR20260063025 AKR 20260063025AKR-20260063025-A

Abstract

The present invention is a method for manufacturing a carbon support with improved porosity and surface hydrophobicity, and more specifically, by activating the carbon support by controlling the pressure factor of an activating gas, a carbon support with improved porosity and surface hydrophobicity can be manufactured.

Inventors

허영정
양희수
손대용
오종길

Assignees

현대자동차주식회사
기아 주식회사

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (18)

A step comprising activating the carbon support by reacting the carbon support and the activating gas in a pressure circulation control manner, Method for manufacturing a carbon support
In paragraph 1, The above carbon support is, Comprising any one selected from the group consisting of porous carbon, activated carbon, carbon black, carbon nanotubes, graphene, and combinations thereof, Method for manufacturing a carbon support
In paragraph 1, The above-mentioned activation gas is, Comprising any one selected from the group consisting of air, oxygen ( O₂ ), carbon dioxide ( CO₂ ), water vapor ( H₂O ), hydrogen peroxide ( H₂O₂ ), ozone ( O₃ ), and combinations thereof, Method for manufacturing a carbon support
In paragraph 1, The above pressure circulation control method is, This means that the pressure of the activation gas supplied to the carbon support circulates between a lower limit pressure and an upper limit pressure, and The above lower limit pressure is 0 bar g to 0.1 bar g , and The above upper pressure satisfies 0.5 bar g to 1 bar g , Method for manufacturing a carbon support
In paragraph 1, The above activation step is, Performed at a temperature of 800℃ to 1,200℃ for 0.1 hours to 6 hours, Method for manufacturing a carbon support
In paragraph 1, Prior to the above activation step, A further comprising the step of oxidizing and heat-treating the carbon support, Method for manufacturing a carbon support
In paragraph 6, The above oxidation heat treatment step is, A process comprising the surface of the carbon support reacting with an oxidizing gas to oxidize, Method for manufacturing a carbon support
In Paragraph 7, The above oxidizing gas comprises any one selected from the group consisting of air, oxygen ( O₂ ), carbon dioxide ( CO₂ ), water vapor ( H₂O ), hydrogen peroxide ( H₂O₂ ), ozone ( O₃ ), and combinations thereof. Method for manufacturing a carbon support
In paragraph 6, The above oxidation heat treatment step is, Performed at a temperature of 150℃ to 600℃ for 0.5 hours to 5 hours, Method for manufacturing a carbon support
In paragraph 1, After the above activation step, A step of reducing and heat-treating an activated carbon support; further comprising Method for manufacturing a carbon support
In Paragraph 10, The above reduction heat treatment step is, A process comprising the surface of the above-mentioned activated carbon support being reduced by reacting with a reducing gas, Method for manufacturing a carbon support
In Paragraph 11, The reducing gas comprises any one selected from the group consisting of hydrogen ( H₂ ), a mixture of hydrogen and an inert gas, ammonia ( NH₃ ), and combinations thereof. Method for manufacturing a carbon support
In Paragraph 10, The above reduction heat treatment step is, Performed at a temperature of 500℃ to 1,100℃ for 0.1 hours to 6 hours, Method for manufacturing a carbon support
In Paragraph 11, The above reduction heat treatment step is, A process comprising reacting the activated carbon support and the reducing gas in a pressure circulation control manner to reduce the surface of the activated carbon support, Method for manufacturing a carbon support
In Paragraph 14, The above-mentioned pressure circulation control method for the reducing gas is, This means that the pressure of the reducing gas supplied to the activated carbon support circulates between a lower limit pressure and an upper limit pressure, and The above lower limit pressure is 0 bar g to 0.1 bar g , and The above upper pressure satisfies 0.5 bar g to 1 bar g , Method for manufacturing a carbon support
Step of oxidizing and heat-treating a carbon support; A step of activating a pretreated carbon support by reacting it with an activating gas; and The method includes the step of reducing the activated carbon support with heat treatment; The above activation step is, A step comprising activating the carbon support by reacting the carbon support and the activating gas in a pressure circulation control manner, Method for manufacturing a carbon support
In Paragraph 16, The above carbon support has hydrophilic groups formed on its surface by oxidative heat treatment, and The above carbon support has the hydrophilic group removed by reduction heat treatment and exhibits hydrophobicity, Method for manufacturing a carbon support
A carbon support manufactured according to any one of claims 1 to 17; and A catalyst metal supported on the carbon support; comprising Catalyst complex for fuel cells.

Description

Manufacturing Method of Carbon Support with Improved Porosity and Surface Hydrophobicity The present invention is a method for manufacturing a carbon support with improved porosity and surface hydrophobicity, and more specifically, by activating the carbon support by controlling the pressure factor of an activating gas, a carbon support with improved porosity and surface hydrophobicity can be manufactured. The electrode catalyst layer constituting a Proton Exchange Membrane Fuel Cell (PEMFC) consists of a carbon support supporting platinum and an ionomer used as a binder. Among these, platinum and alloy catalysts, in which platinum particles are supported on a carbon support, play the most critical role in cell performance and durability; their performance is significantly influenced by the structure and characteristics of the catalyst particles and the carbon support. Therefore, the development of optimized catalysts to ensure the performance and durability of hydrogen electric vehicles is an urgent and critical issue. In these fuel cell catalysts, the carbon support acts as an electron conductor to transfer electrons to the catalyst particles and as a support to disperse the catalyst nanoparticles into smaller sizes to enhance catalytic activity. Accordingly, the porous characteristics of the carbon support allow for the even dispersion of catalysts of several nanometers in size while simultaneously reducing mass transfer resistance in high current density regions; this is the area most directly linked to reducing the amount of metal catalysts used to secure cost competitiveness as well as improving fuel cell performance. Generally, the activation process is a well-known method for improving the porosity of carbon supports, and porosity can be increased through carbon surface oxidation and etching reactions at high temperatures. Typically, activation methods are classified into chemical activation, which involves high-temperature heat treatment in combination with chemical agents, and physical activation, which involves high-temperature heat treatment using oxidizing gases (oxygen, water vapor, carbon dioxide, etc.). Chemical activation has the advantage of high activation efficiency, but it presents economic and environmental problems due to low yield and the need for a washing process to remove additional chemicals. In contrast, although physical activation has low activation efficiency, it offers economic advantages as it does not require an additional washing process, so research is being conducted to improve the activation efficiency of physical activation methods. In particular, physical activation has the advantage of being easier to control reactivity compared to conventional solid-state chemical activation processes because it utilizes oxidizing gases for the reaction. However, there remain issues such as a very low yield resulting from reduced activation efficiency as the forward reaction rate decreases with increasing product concentration over time, and reduced surface durability due to carbon peroxidation. When developing activation processes for fuel cells, it is necessary to simultaneously consider surface durability and yield while expressing porosity. Consequently, to develop next-generation carbon supports that satisfy both durability and performance enhancement, a new synthesis strategy is required to secure the necessary characteristics in a balanced manner. Figure 1 is a graph showing the activation efficiency when activating a carbon support while maintaining a constant pressure of the activation gas. Figure 2 is a graph showing the activation efficiency when the carbon support and the activation gas are reacted by controlling the pressure of the activation gas in the system where the reaction takes place according to the present invention. Figure 3 illustrates the process of converting the surface of a carbon support oxidized through activation to hydrophobic by reducing the surface of the support through heat treatment. Figure 4 shows the carbon supports according to Comparative Example 1 and Example 5 measured by a transmission electron microscope. Figure 5 shows the carbon supports according to Comparative Example 4 and Example 7 measured by a transmission electron microscope. Figure 6 schematically illustrates the crystal structure of carbon to explain the longitudinal crystal size of the carbon support. Figure 7 shows the results of gas adsorption analysis for carbon supports according to Comparative Example 1 and Examples 1 to 4. FIG. 8 shows the detachment curves for carbon supports according to Comparative Example 1 and Examples 1 to 4. Figure 9 shows the results of gas adsorption analysis for carbon supports according to Comparative Example 4, Example 6, and Example 7. FIG. 10 shows the detachment curves for carbon supports according to Comparative Example 4, Example 6, and Example 7. Figure 11 shows the results of analyzing the amount of moisture adsorption and desorption