Macroporous microspheres consisting of thickness-controlled bamboo-like CNTs and flower-like Co3O4 nanoparticles as highly efficient bifunctional oxygen electrocatalysts for Zn–air batteries

Co 3 O 4 nanoparticle-decorated porous hollow microspheres composed of N-doped CNTs are synthesized by spray pyrolysis. When tested as electrocatalysts for a Zn–air battery cathode, they exhibit superior bifunctional oxygen catalytic activities.