Tachikawa T, Tojo S, Fujitsuka M, Majima T. Direct observation of the one-electron reduction of methyl viologen mediated by the CO2 radical anion during TiO2 photocatalytic reactions.
LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004;
20:9441-9444. [PMID:
15491173 DOI:
10.1021/la048100w]
[Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The one-electron reduction of methyl viologen (MV(2+)) mediated by the carbon dioxide radical anion (CO(2)(*-)) during photocatalytic reactions in a colloidal TiO(2) aqueous solution (pH 2) has been investigated by time-resolved absorption spectroscopy. The formation of MV(*+) generated from the one-electron reduction reaction with CO(2)(*-), which is generated from the one-electron oxidation reactions with the photogenerated holes (h(+)), was directly observed. The spectral features of the photogenerated charge carriers and the kinetic analysis of the formation process of MV(*+) revealed that the CO(2)(*-), desorbed from the surface, reacts with MV(2+) via a homogeneous electron-transfer process in the bulk solution.
Collapse