In the catalyst preparation process of proton exchange membrane fuel cells, the uniformity of platinum-carbon catalyst slurry is very important to improve the activity, stability and utilization rate of catalyst.
However, due to the high surface energy of platinum nanoparticles, agglomeration is easy to form, resulting in uneven particle size distribution, which affects the overall performance of the catalyst.
In response to this challenge, Boyi sand mill provides an effective solution to improve the uniformity of platinum-carbon catalyst slurry.
01. The importance of the homogeneity of platinum-carbon catalyst slurry
In the process of preparation of PEMFC catalyst, the uniformity of platinum-carbon catalyst slurry directly affects the uniformity of catalyst layer, and then determines the performance of the battery.
The size distribution of platinum nanoparticles, the dispersion state on the carbon carrier and the overall homogeneity of the slurry are the key factors affecting the catalyst activity.
Therefore, how to disperse platinum nanoparticles effectively and avoid agglomeration becomes the key to improve catalyst performance.
02. Common problems in preparation of platinum-carbon catalyst slurry
Improving catalyst activity: Reducing the size of catalyst particles can effectively improve its catalytic activity, but the particles are easy to form agglomeration when they are not sufficiently dispersed, resulting in an increase in particle size and a decrease in specific surface area, thereby reducing catalytic activity. Improve the stability and uniformity of the catalyst: At present, platinum carbon catalysts for fuel cells require platinum nanoparticles with a size range of 3-5nm, narrow particle size distribution, and uniform dispersion on the carbon carrier.
However, due to the high surface energy of platinum nanoparticles, it is very difficult to prepare catalysts that meet these requirements. Reduce catalyst usage and improve utilization: Agglomeration on the catalyst layer affects oxygen reduction reaction (ORR) kinetics and mass transport, resulting in lower catalyst utilization.
Homogenizing dispersed slurry helps to reduce the amount of catalyst and improve the utilization rate.
Continuous production (stability) : The dispersed platinum-carbon catalyst slurry is prone to reaggregation during storage, and the next process needs to be carried out as soon as possible.
Therefore, the synchronization of the continuous dispersion process with the coating process is essential to achieve continuous production.
03. Application of grinding and dispersion technology of Boyi Sander
With advanced grinding and dispersing technology, Boyi sand mill makes strong shear and impact on materials through high-speed rotating rotor structure and grinding medium.
The agglomeration structure is effectively broken and the uniform dispersion of platinum nanoparticles on the carbon carrier is realized.
The "Z" type homogeneous cavity design further enhances the deagglomerating and loosening action, reduces the size distribution width, and improves the homogeneity of the slurry. High efficiency dispersion: The high shear force and high collision force of Boyi sand mill can effectively disperse platinum nanoparticles, avoid the occurrence of agglomeration phenomenon, and ensure the uniform distribution of platinum nanoparticles on the carbon carrier.
Particle size control: By adjusting the parameters of the type, size and speed of the grinding medium, Boyi sand mill can precisely control the particle size distribution of platinum nanoparticles to meet the strict requirements of PEMFC catalyst for particle size. Continuous production compatibility: Boyi sanders are not only suitable for laboratory-scale research, but also have the potential for large-scale production.
The continuous dispersion process can be synchronized with the coating process of catalyst paste, and the continuous and stable preparation of platinum-carbon catalyst paste can be realized. The paste of platinum-carbon catalyst prepared by the grinding and dispersing technology of Boyi sand mill has better stability.
It can maintain a dispersed state during storage, reduce the risk of reaggregation, and provide a strong guarantee for continuous production.
