Excited-state photoelectrochemical cells for the generation of H/sub 2/ and O/sub 2/ based on Ru(bpy)/sub 3//sup 2 +/

Journal Article · Wed Sep 01 00:00:00 EDT 1982 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00139a037· OSTI ID:5895075

Dressick, W J ^[1]; Meyer, T J; Durham, B; Rillema, D P

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1. Univ of North Carolina, Chapel Hill

Excited-state photoelectrochemical cells are described for the production of H/sub 2/ or O/sub 2/ (or I/sub 2/) in aqueous solution. The cells are based on visible excitation of Ru(bpy)/sub 3//sup 2 +/ followed by oxidative quenching of the resulting charge-transfer excited state(s). In the H/sub 2/ cell, the quencher is paraquat (PQ/sup 2 +/,1,1'-Me/sub 2/-4,4'-bpy/sup 2 +/), and back electron transfer between Ru(bpy)/sub 3//sup 3 +/ and PQ/sup +/ is inhibited by the addition of the reductive scavengers triethanolamine, cysteine, or sodium ethylenediaminetetraacetate, which rapidly reduce Ru(bpy)/sub 3//sup 3 +/ to Ru(bpy)/sub 3//sup 2 +/. The result is to build up PQ/sup +/ in the photolysis cell, which is used to reduce H/sup +/ to H/sub 2/ in a separate cell compartment, at a platinum electrode. In the O/sub 2/ (or I/sub 2/) cell, Co/sub III/(C/sub 2/O/sub 4/)/sub 3//sup 3 -/ (C/sub 2/O/sub 4//sup 2 -/ is oxalate) acts as quencher. Reduction to Co(II) results in rapid aquation to give Co/sup 2 +/(aq), and a back-electron-transfer reaction involving Ru(bpy)/sub 3//sup 3 +/ is avoided. Visible photolysis leads to the production of Ru(bpy)/sub 3//sup 3 +/, which is then used to oxidize OH/sup -/ to O/sub 2/ (or I/sup -/ to I/sub 3//sup -/) in a second cell compartment. Variations in photocurrents in the cells as a function of such variables as pH, quencher concentration, and scavenger concentration are in good agreement with the predictions of a theoretical model developed earlier for a related cell.

• OSTI ID: 5895075
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 21:9; ISSN INOCA
• Country of Publication: United States
• Language: English

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AZINES
BIPYRIDINES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
ELECTROCHEMICAL CELLS
ELECTROLYSIS
ELEMENTS
ENERGY LEVELS
EQUIPMENT
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KINETICS
LYSIS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOELECTROCHEMICAL CELLS
PHOTOELECTROLYSIS
PRODUCTION
PYRIDINES
QUENCHING
REACTION KINETICS
RUTHENIUM COMPLEXES
SOLAR EQUIPMENT
TRANSITION ELEMENT COMPLEXES