Microspherical nitrogen-doped carbon nanotube assembly derived from Pickering droplets

Carbon nanotube assemblies with controlled morphology and tailored architecture offer great potentials for myriad applications, but strategies for their production have remained a significant challenge. Here, we proposed a novel and simple microconfined-annealing strategy, in which a Pickering microdroplet patterned method and unique pyrolysis-stimulated-transformation processes were coupled unprecedentedly, for the fabrication of spherical nitrogen-doped carbon nanotube assemblies (NCNTA). Based on this strategy, the as-prepared superstructures not only retained the micrometer-size and well-defined morphology of the initial Pickering droplets, but also derived a hierarchical pomegranate-like structure where numerous interconnected NCNT particles were encapsulated by a carbon crust. More importantly, the interior architectures were shown to be manipulated through controlling synthesized parameters. Owing to the unique structure and composition of these assemblies, the yielded superstructures exhibited excellent performance and good recyclability in heterogeneous catalysis applications. This synthetic strategy provides new routes to access other micro- or macroscopic materials with novel structures and paves the way to expand their potential applications. (C) 2019 Elsevier Ltd. All rights reserved.