Interface Interaction Dependent Growth of Carbon Nanostructures: An In Situ Study

Controllable synthesis of carbon nanostructures is expected to achieve high electrical, optical, and mechanical performance for various applications. Despite great progress in this field, controllable synthesis of carbon nanostructures, i.e., graphite shells (GSs) and carbon nanotubes (CNTs), is still demanded to be deeply revealed. Here, a strategy is demonstrated to achieve GSs and bamboo CNTs by regulating the interface interaction via in situ pyrolysis of Co phthalocyanine (CoPc) in an environmental transmission electron microscopy (ETEM) at atomic resolution. The results indicate that the catalyst involves the nucleation, combination, and reconstruction of Co/Co3C, the growth modes of the carbon, i.e., base-growth or tip-growth, and nanostructures are dependent on the interface interaction between catalyst and substrate controlled by temperature. High temperature favors tip-growth of bamboo CNTs with larger catalyst nanoparticles (NPs) (approximate to 20 nm), while low temperature favors the base-growth of GSs with smaller NPs (approximate to 10 nm). The average growth rate of 131.3 nm s(-1) at 850 degrees C is about 60 times compared with that at 750 degrees C. The work provides a comprehensive understanding of distinct growth mode of GSs and CNTs at different temperatures, which would be valuable for the controllable growth of carbon nanostructures by catalyst design and engineering.