The influence of catalyst particle size distribution on the yield of vapor-grown carbon fibers produced using the liquid pulse injection technique

Abstract

In the production of vapor-grown carbon fibers, ultrafine iron catalyst particles play an important role in the elongation process of the fibers. The activity of the catalyst particles depends strongly on their sizes. Therefore, in this work, ultrafine iron catalyst particles were produced under various reaction conditions using the liquid pulse injection technique, and were collected to investigate the influence of the reaction conditions on the size distribution of the obtained particles. The varied conditions were, the concentration and amount of ferrocene, which was used as the source of the catalyst material, and the velocity of the carrier gas at a fixed temperature. Each of them had a significant influence on the size distribution. From the obtained distribution curves, the relationship between the amount of catalyst particles having diameters in the range 20–30 nm, and the yield of fibers produced under the same set of reaction conditions was investigated. It was found that the yield increases with the increase in the number of catalyst particles in the size range from 20 to 30 nm. Furthermore, a model was developed to predict the size distribution of particles produced under various reaction conditions. This model was found to well represent the experimental data.