Formation mechanism of Fe-based multi-catalysts for growing CNTs

The application of carbon nanotubes in materials science is rapidly expanding, leading to an increasingly urgent demand for large-scale synthesis. Central to the growth of carbon nanotubes is the development of effective catalysts; thus, the large-scale production of these catalysts becomes crucial for successful carbon nanotube synthesis. Extensive research has been conducted on the mechanisms and regulation of interfacial interactions between metals and supports during catalyst synthesis. This paper is based on the interface interactions between common metal catalysts such as Fe, Co, Ni, and Al₂O₃, and Fe-Co, Fe-Ni, and Fe-Co-Ni metal catalysts were prepared by a one-step method. The catalysts were synthesized through a "one-step process," and the formation mechanisms of bimetallic and trimetallic catalysts, as well as the influence of interfacial interactions on catalyst formation and catalytic activity, were thoroughly investigated. The results indicate that with the involvement of Fe, Co and Ni on the surface of Al₂O₃ maintain a small size morphology due to interfacial interaction. Meanwhile, the nanoparticles form a doped structure with Al₂O₃, effectively avoiding the deactivation of nanoparticles caused by agglomeration. In addition, the three catalysts for growing CNTs were analyzed in order to investigate the effects of different concentrations of metal ratios and time of carbon source on the catalytic activity, which provides new ideas for improving the catalyst design system.