Onium salt effects on p-terphenyl-sensitized photoreduction of water to hydrogen
- Osaka Univ., Suita, Osaka (Japan)
- Notre Dame Radiation Lab., IN (United States)
Salt effects on photoinduced electron-transfer reactions are often discussed and used to control or probe photochemical reactions. p-Terphenyl (TP) sensitizes photocatalytic reduction of water to H{sub 2} under UV irradiation of homogeneous aqueous acetonitrile solution in the presence of triethylamine (TEA) as an electron donor and Ru{sup 3+} as a precursor of cocatalyst, Ru metal colloid. The addition of quaternary onium salts, such as tetraalkylammonium and tetraalkylphosphonium cations, enhances the H{sub 2} evolution, where the onium salts with longer alkyl groups become more effective. Dynamics studies of TP photosensitization reveal that the presence of the salts contributes to stabilization of the radical anion of TP (TP{sup {sm_bullet}{minus}}) formed through reductive quenching of the singlet state of TP ({sup 1}TP{sup *}) and the triplet state of TP ({sup 3}TP{sup *}) by TEA. The TP photosensitization accompanies competitive photo-Birch reduction via TP{sup {minus}}, but the presence of onium salts enhances the lifetime of TP{sup {sm_bullet}{minus}} through the specific interaction, leading to the effective TP-photosensitized H{sub 2} evolution.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 682166
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 25; Other Information: PBD: 24 Jun 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
P-terphenyl-sensitized photoreduction of CO{sub 2} with cobalt and iron porphyrins. Interaction between CO and reduced metalloporphyrins
Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions