resumo
Nickel-doped ceria (Ce1-xNixO2-delta) 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-delta 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-delta 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-delta nanopowders can act as bifunctional electrocatalysts for ORR/OER for potential application in the oxygen electrode of devices such as rechargeable metal-air batteries.
palavras-chave
BOROHYDRIDE FUEL-CELL; CATALYTIC-ACTIVITY; CHEMICAL-PROPERTIES; HYDROGEN OXIDATION; HIGHLY EFFICIENT; OXIDE; COBALT; CE1-XNIXO2-Y; TEMPERATURE; CARBON
categoria
Electrochemistry; Energy & Fuels; Materials Science
autores
Milikic, J; Fuentes, RO; Tasca, JE; Santos, DMF; Sljukic, B; Figueiredo, FML
nossos autores
Diogo Miguel Franco dos Santos
Bolseiro de pós-Doutoramento
Filipe Miguel H Lebre R Figueiredo
Investigador PrincipalProjectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
The authors would like to thank to the Ministry of Education, Science and Technological Development of Republic of Serbia for support within project no. OI172043, and the Science and Technological cooperation agreement MINCyT (Argentina)-MEC (Portugal), Project PO/14/04. Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) is acknowledged for funding a research contract in the scope of programmatic funding UIDP/04540/2020 (D.M.F.S.) and contract no. IST-ID/156-2018 (B.S.).This work was also developed within the scope of the projects UniRCell (SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), financed by national funds through the FCT/MEC, and CICECO Aveiro Institute of Materials UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC).