Electrocatalytic four-electron reduction of dioxygen by iridium porphyrins adsorbed on graphite

Journal Article · Wed Nov 26 04:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00284a067· OSTI ID:6956873

Collman, J P; Kim, K

The electrocatalytic reduction of dioxygen by macrocyclic transition-metal complexes adsorbed on electrodes has been studied extensively in conjunction with the search for an inexpensive cathode material for oxygen fuel cells. The authors and other laboratories have shown that dicobalt cofacial porphyrin dimers can catalyze dioxygen reduction to water without producing significant amounts of hydrogen peroxide. To our knowledge, however, no monomeric macrocyclic metal complex has been reported to catalyze the direct four-electron reduction of dioxygen in acidic solution. In a survey of electrocatalytic oxygen reduction by various metalloporphyrins adsorbed on activated carbon, iridium complexes were reported to be the most active catalysts. Since the reduction product and the reaction pathway had not been elucidated in that work, they were prompted to study the electrocatalytic activity of iridium porphyrins toward dioxygen reduction. Here they report the first observation of a direct four-electron reduction of dioxygen catalyzed by Ir(OEP)H adsorbed on graphite in acidic electrolyte solution.

• Research Organization: Stanford Univ., CA
• OSTI ID: 6956873
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:24; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300503* -- Fuel Cells-- Materials
Components
& Auxiliaries
300505 -- Fuel Cells-- Electrochemistry
Mass Transfer & Thermodynamics
ADSORPTION
CARBON
CARBOXYLIC ACIDS
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CATHODES
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DATA
ELECTROCHEMISTRY
ELECTRODES
ELECTROLYTES
ELEMENTAL MINERALS
ELEMENTS
EXPERIMENTAL DATA
GRAPHITE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
IRIDIUM COMPLEXES
MINERALS
NONMETALS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PORPHYRINS
REDUCTION
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENT COMPLEXES