Popcorn-like Co3O4 Nanoparticles Confined in a Three-Dimensional Hierarchical N-doped Carbon Nanotube Network As a Highly-Efficient Trifunctional Electrocatalyst for Zinc–air Batteries and Water Splitting Devices

A novel unique 3D hierarchical structural electrocatalyst is synthesized, where popcorn-like Co3O4 nanoparticles coated with N-doped amorphous carbon anchor onto the tips of N-doped carbon nanotubes (NCNTs), and the NCNTs grow on carbon nanofiber.