Photochemical conversion of solar energy. Annual progress report, 1 January--31 Dec 1976. [Iron--thionine and iron--thiozine]

Technical Report · Tue May 31 04:00:00 EDT 1977

OSTI ID:5266642

Lichtin, N D

Basic and applied aspects of thin-layer, totally-illuminated (TI-TL) iron-thiazine photogalvanic cells were investigated. I(sc) varies linearly with photostationary concentration of leucodye. Slopes indicate that I(sc) < 25% of the diffusion-controlled limit. Cyclic voltammetry shows that electron transfer between the thionine-leucothionine (TH(+)/TH/sup 4/(+2) couple and SnO/sup 2/ is kinetically controlled, rectification reduces the efficiency of oxidation of TH/sup 4/(+2), the mechanism is EE and the process is more nearly reversible in neat H/sup 2/O than in 50 v/v% aq CH/sup 3/CN. The SnO/sup 2/ electrode is highly irreversible to Fe(+3)/Fe(+2); oxidation of Fe(+2) is particularly inhibited. Fe(+3)/Fe(+2) is more reversible at SnO/sup 2/ in 50 v/v% aq CH3CN than in water. TH4(+2) is strongly and TH(+) is weakly adsorbed at SnO/sup 2/. E(0) for TH(+)/TH/sup 2/(+) and TH2(+)/TH4(+2) was determined with the aid of photostationary state decay rate data and used together with EFB data to determine the energy diagram for the interface between SnO/sup 2/ and iron-thionine solutions. The potentials for TH/sup 4/(+2)/TH/sup 2/(+) and Fe(+3)/Fe(+2) fall in the band gap region of SnO/sup 2/. Output of the iron-thionine TI-TL SnO/sup 2//Pt cell with a number of new binary and ternary solvent systems was investigated. The best was a 10 w/w% solution of non-ionic surfactant Brij-35 (n-C/sup 12/H/sup 25/(OC/sup 2/H/sup 4/)/sup 23/OH in 25v% CH/sup 3/CN-75v% H/sup 2/O. VocxIsc was approx. 35% higher in this solvent than in 50 v/v% CH/sup 3/CN. Investigation of other dyes and redox quenchers did not reveal any photoredox system as efficient in the TI-TL SnO/sup 2//Pt cell as iron-thionine.

• Research Organization: Boston Univ., MA (USA). Dept. of Chemistry
• OSTI ID: 5266642
• Report Number(s): PB-270058
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
&amp; Thermochemical Conversion-- (1980-)
AMINES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CURRENTS
DYES
ELECTRIC CURRENTS
ELECTROCHEMICAL CELLS
ELECTRON TRANSFER
ELEMENTS
HETEROCYCLIC COMPOUNDS
IRON
METALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOGALVANIC CELLS
PLATINUM
PLATINUM METALS
RESEARCH PROGRAMS
THIONINE
TIN COMPOUNDS
TIN OXIDES
TRANSITION ELEMENTS
VOLTAMETRY