Non noble metal catalyst for cathode of direct methanol fuel cell, and preparation method

A methanol fuel cell and non-precious metal technology, applied in the direction of catalyst activation/preparation, battery electrodes, catalyst carriers, etc., can solve problems such as unstable electrocatalysts, affecting battery performance, and expensive prices

Inactive Publication Date: 2007-05-09
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there is a large gap between the performance of direct methanol fuel cells and commercial requirements. Another problem is that the methanol in the anode passes through the proton exchange membrane to reach the cathode, and will oxidize on the commonly used carbon-supported platinum cathode, poisoning the catalyst. This not only makes methanol not fully used, but also seriously affects the performance of the battery
[0004] It has been discovered in the 1960s that transition metal macrocycles can be used as catalysts for oxygen reduction, but these transition metal chelates are unstable electrocatalysts when used directly
Existing catalysts are generally noble metals, which are relatively expensive and prone to poisoning

Method used

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  • Non noble metal catalyst for cathode of direct methanol fuel cell, and preparation method
  • Non noble metal catalyst for cathode of direct methanol fuel cell, and preparation method
  • Non noble metal catalyst for cathode of direct methanol fuel cell, and preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Molybdenum tetraphenylporphyrin and Vulcan XC-72 activated carbon powder were dissolved in tetrahydrofuran at a mass ratio of 1:9, and ultrasonicated for 60 minutes; the above solution was stirred at room temperature, evaporated to dryness, and dried at 80°C. The obtained powder was sealed in a quartz glass tube, and ammonia gas was introduced at a flow rate of 1 l / min. The heat treatment temperature was controlled at 700°C, and the reaction was carried out at this temperature for 3 hours. Then, the heating was stopped and cooled to room temperature to obtain a MoN / C catalyst. The lens photo shows that the particle size of MoN is 5-6nm. According to the cathode polarization curve attached in Figure 2, the reduction onset potential of oxygen on the catalyst is -0.1V, and the area specific activity is 3.1mA / cm 2 , and the area specific activity of the carbon-supported platinum catalyst is 1.5mA / cm when the relative rotation speed and scan rate are consistent 2 , increased...

Embodiment 2

[0024] Molybdenum octaethylporphyrin and Vulcan XC-72 activated carbon powder were dissolved in acetone at a mass ratio of 1:1, and ultrasonicated for 50 minutes; the above solution was stirred at room temperature, evaporated to dryness, and dried at 60°C. The obtained powder was sealed in a quartz glass tube, and ammonia gas was introduced at a flow rate of 0.5 l / min. The heat treatment temperature was controlled at 700° C., and the reaction was carried out at this temperature for 4 hours. Then, the heating was stopped and cooled to room temperature to obtain a MoN catalyst. The lens photo of accompanying drawing 2 shows that the particle size of the catalyst is 5-6nm. The electrochemical cathodic polarization curve and the chronocurrent curve show that the performance of the catalyst is better than that of the carbon-supported platinum electrocatalyst.

Embodiment 3

[0026] Molybdenum tetramethoxyporphyrin and Vulcan XC-72 activated carbon powder were dissolved in N-N dimethylacetamide at a mass ratio of 2:3, ultrasonicated for 50 minutes; the above solution was stirred at room temperature, evaporated to dryness, and dried at 70°C. The obtained powder was sealed in a quartz glass tube, and ammonia gas was introduced at a flow rate of 2 l / min. The heat treatment temperature was controlled at 600° C., and the reaction was carried out at this temperature for 5 hours. Then, the heating was stopped and cooled to room temperature to obtain a MoN catalyst. The lens photos show that the particle size of the catalyst is 5-6nm. The electrochemical cathodic polarization curve and the chronocurrent curve show that the performance of the catalyst is better than that of the carbon-supported platinum electrocatalyst.

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Abstract

Existing catalysts are noble metals generally, which are costly and easy poisoning. Active component of the disclosed catalyst is transition metal nitride. Carrier is activated carbon powder Vulcan XC-72. Percentage content of mass of transition metal nitride in active component is 1-6%. The preparation method includes steps: dissolving macrocyclic compound of transition metal, Vulcan XC-72 into organic solvent, and carrying out ultrasonic action for 30-60 minutes; stirring up and drying out the said solution under normal temperature, and obtaining powder after drying; loading the powder to closed container and letting ammonia into the container; controlling temperature of heat treatment at 600-1000 deg.C, and time as 0.5-10h so as to obtain the catalyst after natural cooling. Area ratio activity of carbon carried platinum catalyst is 1.5mA/cm2, and the disclosed carbon carried nitride catalyst reaches to 3.1 mA/cm2. Features are: simple flow and easy controlled procedure.

Description

technical field [0001] The invention belongs to the field of fuel cell catalysts. Background technique [0002] Direct methanol fuel cell is a kind of proton exchange membrane fuel cell, which uses solid polymer membrane as electrolyte and liquid or gaseous methanol as fuel. It is a kind of fuel cell and has many advantages of fuel cells: no pollution, quiet and efficient, and conducive to environmental protection. In addition, it does not require intermediate reforming or conversion devices, is light in weight and small in size, and simplifies battery design and operation. Due to the many advantages mentioned above, it is especially suitable for mobile power sources for various purposes, such as mobile phones, notebook computers and electric vehicle power sources. [0003] In direct methanol fuel cells, Pt / C catalysts are often used as cathode oxygen reduction electrocatalysts and are the most studied fuel cell catalysts. Since the noble metal Pt is relatively rare and e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/90B01J27/00B01J27/24B01J32/00B01J37/00
CPCY02E60/50
Inventor 夏定国刘淑珍邱文革
Owner BEIJING UNIV OF TECH
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