Photo-electro-oxidation of alcohols on titanium dioxide thin film electrodes
- Univ. de Buenos Aires (Argentina)
- Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Unidad de Actividad Quimica
The photo-electro-oxidation on titanium dioxide film electrodes of methanol, 2-propanol, and tert-butyl alcohol has been studied by measuring the transient photocurrents observed during the early stages of illumination. Transients and steady-state photocurrents, measured at different applied potentials and methanol concentrations, were compared with model predictions. The numerical solution of the differential equations corresponding to methanol photo-electro-oxidation, as well as the advanced experimental evidence, supports the hypothesis that surface hole trapping as {single_bond}OH{sup {sm_bullet}} mediates the charge transfer to methanol. Formation of {single_bond}OH{sup {sm_bullet}} accounts for the high initial photocurrents, its rapid decay being due to recombination. The rate of oxidation of methanol is then determined by the rate of reaction between {single_bond}OH{sup {sm_bullet}} and CH{sub 3}OH located in the interfacial region. The oxidation of {sup {sm_bullet}}CH{sub 2}OH to CH{sub 2}O, through the injection of an electron into the conduction band (current doubling), gives rise to an increase in photocurrent; steady state values are later attained. As a consequence, a minimum transient is observed. The minimum is marginally observable in tert-butyl alcohol solutions, in line with the properties of the respective radicals.
- OSTI ID:
- 682080
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 26 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
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