Silicon nanocages as effective catalysts for oxygen reduction reaction  

Abstract

Here, the catalytic activity of Fe-C44 and Fe-Si44 for oxygen reduction reaction by effective mechanisms are examined. The nanocatalysts (Fe-C44 and Fe-Si44) for ORR mechanisms are suggested and results are compared with Pt-based catalysts. Results indicated that the H2O on surfaces of Fe-C44 and Fe-Si44 nanocages are physically absorbed and it means that H2O is easily desorbed from Fe-C44 and Fe-Si44 nanocages. The adsorption OOH on Fe-C44 and Fe-Si44 nanocages has higher Eadsorption than O2 adsorption and also dissociation of O2 molecules on Fe-C44 and Fe-Si44 nanocages has high activation barrier energy. The nanocage-*OH, nanocage-*OH and H2O and nanocage-*O and H2O formation are rate-determining steps in mechanisms 1, 2 and 3. It can be demonstrated that pathway 1 is effective mechanism for ORR on Fe-C44 and Fe-Si44 nanocages. Results shown that the overpotential of ORR on Fe-C44 and Fe-Si44 nanocages are lower than Pt catalysts.