Synergy of Cobalt and Silver Microparticles Electrodeposited on Glassy Carbon for the Electrocatalysis of the Oxygen Reduction Reaction: An Electrochemical Investigation.
The combination of two different metals, each of them acting on different steps of the oxygen reduction reaction (ORR), yields synergic catalytic effects. In this respect, the electrocatalytic effect of silver is enhanced by the addition of cobalt, which is able to break the O-O bond of molecular oxygen, thus accelerating the first step of the reduction mechanism. At the same time, research is to further reduce the catalyst's cost, reducing the amount of Ag, which, even though being much less expensive than Pt, is still a noble metal. From this point of view, using a small amount of Ag together with an inexpensive material, such as graphite, represents a good compromise. The aim of this work was to verify if the synergic effects are still operating when very small amounts of cobalt (2-10 μg·cm(-2)) are added to the microparticles of silver electrodeposited on glassy carbon, described in a preceding paper from us. To better stress the different behaviour observed when cobalt and silver are contemporarily present in the deposit, the catalytic properties of cobalt alone were investigated. The analysis was completed by the Levich plots to evaluate the number of electrons involved and by Tafel plots to show the effects on the reaction mechanism.
Department of Chemistry, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy. claudio.zafferoni@unifi.it.
Claudio
C
Zafferoni
WestCHEM, School of Chemistry, University of Glasgow, University Avenue, G12 8QQ Glasgow, UK. g.cioncoloni.1@research.gla.ac.uk.
Giacomo
G
Cioncoloni
Department of Chemistry, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy. marialuisa.foresti@unifi.it.
Maria Luisa
ML
Foresti
Department of Chemistry, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy. luigi.dei@unifi.it.
Luigi
L
Dei
Department of Chemistry, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy. carretti@csgi.unifi.it.
Emiliano
E
Carretti
Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino (Fi), Italy. francesco.vizza@iccom.cnr.it.
Francesco
F
Vizza
Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino (Fi), Italy. alessandro.lavacchi@iccom.cnr.it.
Alessandro
A
Lavacchi
Department of Chemistry, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy. m.innocenti@unifi.it.
Massimo
M
Innocenti
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004595:Electroplating / Q000379:methods*; D005898:Glass / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
D003035:Cobalt; D012834:Silver; D002244:Carbon; D010100:Oxygen
ORR; cobalt; electrodeposition; silver