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 Co 3 O 4 nanoparticles coated with N-doped amorphous carbon anchor onto the tips of N-doped carbon nanotubes (NCNTs), and the NCNTs grow on carbon nanofiber.