Study of Oxygen Reduction Reaction on Polycrystalline Rhodium in Acidic and Alkaline Media

This study examines the kinetics and mechanism of the oxygen reduction reaction (ORR) on a polycrystalline rhodium electrode (Rh(poly)) in acidic and alkaline media, using rotating disc electrode measurements. This study found that the ORR activity of the Rh(poly) electrode decreases in the order of...

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Bibliographic Details
Published in:Catalysts 2024-05, Vol.14 (5), p.327
Main Authors: Golubović, Jelena, Varničić, Miroslava, Štrbac, Svetlana
Format: Article
Language:English
Subjects:
Adsorption
Analysis
Anions
Chemical reduction
Electrodes
Electrons
Fuel cells
Hydrogen peroxide
Identification and classification
Kinetics
Methods
Nanoparticles
Oxidation
Oxidation-reduction reaction
oxygen reduction
Oxygen reduction reactions
Perchloric acid
polycrystalline rhodium
Polycrystalline semiconductors
Polycrystals
Properties
reaction mechanism
Rhodium
rotating disc
Rotating disks
Single crystals
Sulfuric acid
Voltammetry
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Summary:This study examines the kinetics and mechanism of the oxygen reduction reaction (ORR) on a polycrystalline rhodium electrode (Rh(poly)) in acidic and alkaline media, using rotating disc electrode measurements. This study found that the ORR activity of the Rh(poly) electrode decreases in the order of 0.1 M NaOH > 0.1 M HClO4 > 0.05 M H2SO4 concerning the half-wave potentials. The Tafel slopes for ORR on Rh(poly) in the cathodic direction are 60 and 120 mV dec−1 at low and high overpotentials, respectively, in perchloric acid and alkaline solutions. However, strongly adsorbed sulfate anions hinder the ORR on Rh(poly) in sulfuric acid, leading to higher Tafel slopes. The highest ORR activity of Rh(poly) in an alkaline media suggests the promoting role of the specifically adsorbed OH− anions and RhOH. In all cases, ORR on Rh(poly) proceeds through the 4e-series reaction pathway.
ISSN:2073-4344
2073-4344
DOI:10.3390/catal14050327