Fe–Mo/Kaolin Catalyst Optimization and Characterization for the Production of Carbon Nanotube Using the Wet Impregnated Method

Abstract

The synthesis of the bimetallic Fe–Mo/kaolin catalyst for carbon nanotube (CNT) production involves the pre-calcination and calcination processes, employing the wet impregnated method. In the pre-calcination stage, we explored the  effects of synthesis parameters such as oven drying temperature, mass of kaolin, and heating time using a 2³ factorial experimental design, ultimately obtaining the highest yield sample. In the calcination phase, the effect of temperature and heating time using a 2² factorial experimental design was examined. The as-prepared nanoparticles were characterized by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), thermogravimetric analysis (TGA), differential thermal analysis (DTA), x-ray diffraction (XRD), and Brunauer-Emmet-Teller (BET). SEM/TGA revealed a well-dispersed metallic particle on the kaolin support and its ability to maintain high thermal stability. XRD analysis of the catalyst confirmed its crystal nature and the presence of mixed oxides of different intensities, conducive to CNT growth. The optimum yield obtained after oven drying was 75.25%. At the optimum calcination temperature of 300° C and calcination time of 16 hours, BET analysis determined the surface area and pore volume. For kaolin, the surface area and pore volume were 1.932x10² m²/g and 1.762x10^-1 cc/g, respectively. The optimal calcine sample showed increment for both the surface area (3.103 x10² m²/g) and the pore volume (2.459 x10^-1cc/g) making it more suitable for CNT production. Lastly, statistical analysis showed that heating time, calcination time, temperature, and mass of kaolin have a significant influence on the catalyst yield in CNT.