Nickel-Doped Ceria Bifunctional Electrocatalysts for Oxygen Reduction and Evolution in Alkaline Media
Jadranka Milikić,
Rodolfo O. Fuentes,
Julia E. Tasca,
Diogo M. F. Santos,
Biljana Šljukić,
Filipe M. L. Figueiredo
Affiliations
Jadranka Milikić
University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12–16, 11158 Belgrade, Serbia
Rodolfo O. Fuentes
Instituto de Nanociencia y Nanotecnología, Departamento de Física, Centro Atómico Constituyentes, CNEA-CONICET, Av. Gral. Paz 1499, San Martín, Buenos Aires B1650, Argentina
Julia E. Tasca
CIFICEN (UNCPBA-CICPBA-CONICET), Facultad de Ingeniería–UNCPBA, Av. Del Valle 5737, Olavarría B74001WI, Argentina
Diogo M. F. Santos
Center of Physics and Engineering of Advanced Materials (CeFEMA), Laboratory for Physics of Materials and Emerging Technologies (LaPMET), Chemical Engineering Department, Instituto Superior Técnico, Universidade de Lisboa, 1049–001 Lisbon, Portugal
Biljana Šljukić
University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12–16, 11158 Belgrade, Serbia
Filipe M. L. Figueiredo
CICECO, Physics Dept., University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
Nickel-doped ceria (Ce1−xNixO2−δ) nanopowders (7 to 5 nm in size) synthesized by the cation complexation method with 5, 10, 15, and 20 Ni at.% are studied with respect to their electrochemical activity for the oxygen reduction (ORR) and oxygen evolution (OER) reactions in alkaline medium. One finds good bifunctional electrocatalytic activity of the four Ce1−xNixO2−δ electrocatalysts. The Tafel analysis of the ORR in the 0.57–0.78 V vs. RHE potential window leads to slopes in the 70–108 mV dec−1 range. The number of electrons exchanged during ORR is between 2 and 2.7. The OER Tafel slopes are determined to be in the range 192 –281 mV dec−1. OER activation energies are found to range between 28 and 43 kJ mol−1. The specific capacitance of Ce1−xNixO2−δ electrocatalysts measured at a scan rate of 100 mV s−1 varies between 0.7 and 1.4 Fg−1. The results demonstrate that Ce1−xNixO2−δ nanopowders can act as bifunctional electrocatalysts for ORR/OER for potential application in the oxygen electrode of devices such as rechargeable metal–air batteries.
