Characterization of doped iron oxide electrodes for the photodissociation of water: stability, optical, and electronic properties

Journal Article · Wed Aug 01 04:00:00 EDT 1984 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2115959· OSTI ID:5169708

Turner, J E; Hendewerk, M; Parmeter, J; Neiman, D; Somorjai, G A

A characterization of optical and electronic properties is presented for p-type (Mg-doped) and n-type (Si-doped) iron oxides used in the photoelectrolysis of water. Photocurrent vs. wavelength spectra for these electrodes indicate that ..cap alpha..-Fe/sub 2/O/sub 3/ is the active optical component for both p-type and n-type materials. Band-edge locations for p-type and n-type iron oxides in sodium hydroxide aqueous solution are determined from differential capacitance measurements. The thermodynamic feasibility of the catalytic photodissociation of water without external potential is demonstrated for a short-circuited p/n diode assembly on an energy level diagram of the electrode/electrolyte interfaces. The open-circuit voltage (V/sub oc/) and short-circuit current (I/sub sc/) generated by the p/n assembly as a function of the intensity of laser irradiation indicate that these doped iron oxides are low mobility, high carrier density semiconductors. Photo-oxidation of water at the n-type anode is verified through oxygen detection. Gas evolution is monitored from an operating diode assembly using mass spectrometry and isotopically labeled water (H/sub 2//sup 18/O). Photocurrent from these p/n assemblies show excellent long-term stability in aqueous solution and Auger analysis of the semiconductor surfaces indicates no evidence of electrode dissolution.

• Research Organization: Univ. of California, Berkeley
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5169708
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 131:8; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
ALKALINE EARTH METAL COMPOUNDS
AQUEOUS SOLUTIONS
CHALCOGENIDES
CHEMISTRY
DATA
DISPERSIONS
DISSOCIATION
DOPED MATERIALS
ELECTRICAL PROPERTIES
ELECTRODES
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
INFORMATION
IRON COMPOUNDS
IRON OXIDES
MAGNESIUM COMPOUNDS
MATERIALS
MIXTURES
NUMERICAL DATA
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMISTRY
PHYSICAL PROPERTIES
SEMICONDUCTOR MATERIALS
SILICON COMPOUNDS
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
WATER