Electrooxidation of methanol on iridium in acidic solutions: electrocatalysis and surface characterization by infrared spectroscopy

Journal Article · Thu Apr 23 00:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100293a020· OSTI ID:6542557

Aramata, A; Yamazaki, T; Kunimatsu, K; Enyo, M

Electrooxidation of methanol was studied on iridium in H/sub 2/SO/sub 4/ and CHlO/sub 4/ solutions in connection with catalytic activities of the electrode in various oxidation states and of the adsorbed CO observed by infrared spectrometry. Iridium was found to show higher catalytic activity than platinum at low positive potential regions. The catalytic activity of iridium decreased with time at a constant-potential polarization and was inhibited by the introduction of CO gas. In situ infrared spectra were observed in the measurement conditions of electrode potential modulation and of constant electrode potential. The spectra for the above different conditions agreed in the wavenumber region of the spectra but not in absorbance intensity or in its relative values at different electrode potentials. The spectral maxima of the adsorbed CO, derived from methanol, were 2045 cm/sup -1/ at 0.2 V (vs. RHE) and 2054 cm/sup -1/ at 0.5 V. These maxima were shifted 20 cm/sup -1/ to higher wavenumber by the addition of CO gas. The catalytic activity of iridium was discussed in relation to redox coupling of iridium species in different oxidation states, the rate of their redox coupling, and the adsorbed CO observed by infrared spectroscopy.

• Research Organization: Hokkaido Univ., Sapporo, Japan
• OSTI ID: 6542557
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:9; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

090110 -- Hydrocarbon Fuels-- Properties-- (1979-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ALCOHOLS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ELECTRIC POTENTIAL
ELECTROCATALYSTS
ELECTRODES
ELEMENTS
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
INFRARED SPECTRA
INORGANIC ACIDS
IRIDIUM
METALS
METHANOL
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PERCHLORIC ACID
PLATINUM METALS
SPECTRA
SPECTROSCOPY
SULFURIC ACID
TRANSITION ELEMENTS