Dual-Silica Template-Mediated Synthesis of Nitrogen-Doped Mesoporous Carbon Nanotubes for Supercapacitor Applications

1D carbon nanotubes have been widely applied in many fields, such as catalysis, sensing and energy storage. However, the long tunnel-like pores and relatively low specific surface area of carbon nanotubes often restrict their performance in certain applications. Herein, a dual-silica template-mediated method to prepare nitrogen-doped mesoporous carbon nanotubes (NMCTs) through co-depositing polydopamine (both carbon and nitrogen precursors) and silica nanoparticles (the porogen for mesopore formation) on a silica nanowire template is proposed. The obtained NMCTs have a hierarchical pore structure of large open mesopores and tubular macropores, a high specific surface area (1037 m² g^-1 ), and homogeneous nitrogen doping. The NMCT-45 (prepared at an interval time of 45 min) shows excellent performance in supercapacitor applications with a high capacitance (373.6 F g^-1 at 1.0 A g-¹ ), excellent rate capability, high energy density (11.6 W h kg^-1 at a power density of 313 W kg^-1 ), and outstanding cycling stability (98.2% capacity retention after 10 000 cycles at 10 A g^-1 ). Owing to the unique tubular morphology, hierarchical porosity and homogeneous N-doping, the NMCT also has tremendous potential in electrochemical catalysis and sensing applications.