Nickel-Doped Ceria Bifunctional Electrocatalysts for Oxygen Reduction and Evolution in Alkaline Media

Nickel-doped ceria (Ce1?xNixO2??) nanopowders (7 to 5 nm in size) synthesized by the cation complexation method with 5, 10, 15, and 20 Ni at.% are studied respect their electrochemical activity for oxygen reduction (ORR) evolution (OER) reactions alkaline medium. One finds good bifunctional electrocatalytic of four Ce1?xNixO2?? electrocatalysts. The Tafel analysis ORR 0.57–0.78 V vs. RHE potential window leads slopes 70–108 mV dec?1 range. number electrons exchanged during is between 2 2.7. OER determined be range 192 –281 dec?1. activation energies found 28 43 kJ mol?1. specific capacitance electrocatalysts measured at a scan rate 100 s?1 varies 0.7 1.4 Fg?1. results demonstrate that can act as ORR/OER application electrode devices such rechargeable metal–air batteries.