Achieving CNTs Growth by Inducing Nanoparticle Nucleation via Non-Active Fe2O3 Clusters Anchored on the α-Al2O3 Surface

Abstract

This research presents a regulation strategy of constructing a heterogeneous bilayer catalyst of Fe and Al₂O₃, namely, Fe–Al₂O₃, through interfacial interaction and particle nucleation, in order to modulate the size and catalytic activity of Fe sites and achieve the growth of carbon nanotubes (CNTs). Through temperature control, the noncatalytically active Fe₂O₃ clusters on the surface of Al₂O₃ are exposed, inducing multiple nucleation of Fe clusters on its surface. Under the synergistic effect of the confinement at the Fe–Al₂O₃ interface, the fabrication of small Fe nanoparticles is accomplished. The results indicate that the catalytically active Fe nanoparticles have a diameter of approximately 10 nm, and the grown CNTs have a diameter of approximately 15 nm. Based on the systematic characterization results, the nonactive Fe₂O₃ clusters confined by strong interfacial interaction induce multiple nucleation of Fe on their surface during multiple loading processes, facilitating the formation of nanoparticles. Additionally, the strong interaction between Al₂O₃ and Fe induces the formation of FeAl₄O₈, thereby enhancing the thermal stability of the nanoparticles. In conclusion, the targeted regulation of the interfacial interaction of the catalyst active sites offers guidance for the low-cost and large-scale preparation of small nanoparticle catalyst particles.