Cobalt-based multicomponent nanoparticles supported on N-doped graphene as advanced cathodic catalyst for zinc-air batteries

To improve the efficiency of cathodic oxygen reduction reaction (ORR) in zinc-air batteries (ZABs), an adsorption-complexation-calcination method was proposed to generate cobalt-based multicomponent nanoparticles comprising Co, Co3O4 and CoN, as well as numerous N heteroatoms, on graphene nanosheets (Co/Co3O4/CoN/NG). The Co/Co3O4/CoN nanoparticles with the size of less than 50 nm are homogeneously dispersed on N-doped graphene (NG) substrate, which greatly improve the catalytic behaviors for ORR. The results show that the half-wave potential is as high as 0.80 V vs. RHE and the limiting current density is 4.60 mA center dot cm(-2), which are close to those of commercially available platinum/carbon (Pt/C) catalysts. Applying as cathodic catalyst for ZABs, the battery shows large specific capacity and open circuit voltage of 843.0 mAh center dot g(-1) and 1.41 V, respectively. The excellent performance is attributed to the efficient two-dimensional structure with high accessible surface area and the numerous multiple active sites provided by highly scattered Co/Co3O4/CoN particles and doped nitrogen on the carbon matrix.