Abstract:
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, Co
3O
4 and CoN, as well as numerous N heteroatoms, on graphene nanosheets (Co/Co
3O
4/CoN/NG). The Co/Co
3O
4/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∙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∙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/Co
3O
4/CoN particles and doped nitrogen on the carbon matrix.