Photooxidation of organic mixtures on biased TiO 2 films
Processes that occur in the TiO 2 -photocatalysis of binary aqueous solutions containing model photolytes with different affinity for the TiO 2 surface (methanol and oxalic and salicylic acids) are analyzed from the photoelectrochemical response of TiO 2 films under bias in a time window of 1-100 s....
Guardado en:
| Autores principales: | , , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0013936X_v35_n20_p4132_Calvo |
| Aporte de: |
| id |
todo:paper_0013936X_v35_n20_p4132_Calvo |
|---|---|
| record_format |
dspace |
| spelling |
todo:paper_0013936X_v35_n20_p4132_Calvo2023-10-03T14:11:39Z Photooxidation of organic mixtures on biased TiO 2 films Calvo, M.E. Candal, R.J. Bilmes, S.A. Photolytes Binary mixtures Charge transfer Electrolytes Methanol Photoelectricity Photooxidation Titanium oxides Photocatalysis electrolyte methanol oxalic acid salicylic acid titanium dioxide aqueous solution binary mixture film organic compound oxidation titanium dioxide adsorption aqueous solution article catalysis film illumination irradiation photooxidation Adsorption Coloring Agents Kinetics Methanol Organic Chemicals Oxalic Acid Oxidation-Reduction Photochemistry Salicylic Acid Titanium Water Pollutants, Chemical Processes that occur in the TiO 2 -photocatalysis of binary aqueous solutions containing model photolytes with different affinity for the TiO 2 surface (methanol and oxalic and salicylic acids) are analyzed from the photoelectrochemical response of TiO 2 films under bias in a time window of 1-100 s. Long-lived oxidized intermediates produced upon illumination at 0.6 V SCE are detected by cathodic sweep run in the dark after irradiation. The main conclusion derived from this work is that a scheme of competitive kinetics describes only those cases in which one of the components is weakly or nonadsorbed on TiO 2 , whereas for two photolytes with high affinity for the surface cooperative effects may occur. The methanol-oxalate system is quantitatively modeled by considering that oxalate forms surface complexes with different reactivity and a parallel pathway for hole transfer to -OH and adsorbed oxalate. In this case as well as for electrolytes containing methanol and salicylate photooxidation of methanol (with low affinity for the surface) via intermediates formed by reaction with trapped holes (- • OH) is partially or fully suppressed. For electrolytes containing oxalic and salicylic acids in which both components chemisorb on TiO 2 the photoelectrochemical response depends on preadsorption, the photooxidation pathways deviates those of single component systems, and there is remotion of salicylate adsorbed byproducts assigned to cooperative effects. Fil:Calvo, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Candal, R.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Bilmes, S.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0013936X_v35_n20_p4132_Calvo |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Photolytes Binary mixtures Charge transfer Electrolytes Methanol Photoelectricity Photooxidation Titanium oxides Photocatalysis electrolyte methanol oxalic acid salicylic acid titanium dioxide aqueous solution binary mixture film organic compound oxidation titanium dioxide adsorption aqueous solution article catalysis film illumination irradiation photooxidation Adsorption Coloring Agents Kinetics Methanol Organic Chemicals Oxalic Acid Oxidation-Reduction Photochemistry Salicylic Acid Titanium Water Pollutants, Chemical |
| spellingShingle |
Photolytes Binary mixtures Charge transfer Electrolytes Methanol Photoelectricity Photooxidation Titanium oxides Photocatalysis electrolyte methanol oxalic acid salicylic acid titanium dioxide aqueous solution binary mixture film organic compound oxidation titanium dioxide adsorption aqueous solution article catalysis film illumination irradiation photooxidation Adsorption Coloring Agents Kinetics Methanol Organic Chemicals Oxalic Acid Oxidation-Reduction Photochemistry Salicylic Acid Titanium Water Pollutants, Chemical Calvo, M.E. Candal, R.J. Bilmes, S.A. Photooxidation of organic mixtures on biased TiO 2 films |
| topic_facet |
Photolytes Binary mixtures Charge transfer Electrolytes Methanol Photoelectricity Photooxidation Titanium oxides Photocatalysis electrolyte methanol oxalic acid salicylic acid titanium dioxide aqueous solution binary mixture film organic compound oxidation titanium dioxide adsorption aqueous solution article catalysis film illumination irradiation photooxidation Adsorption Coloring Agents Kinetics Methanol Organic Chemicals Oxalic Acid Oxidation-Reduction Photochemistry Salicylic Acid Titanium Water Pollutants, Chemical |
| description |
Processes that occur in the TiO 2 -photocatalysis of binary aqueous solutions containing model photolytes with different affinity for the TiO 2 surface (methanol and oxalic and salicylic acids) are analyzed from the photoelectrochemical response of TiO 2 films under bias in a time window of 1-100 s. Long-lived oxidized intermediates produced upon illumination at 0.6 V SCE are detected by cathodic sweep run in the dark after irradiation. The main conclusion derived from this work is that a scheme of competitive kinetics describes only those cases in which one of the components is weakly or nonadsorbed on TiO 2 , whereas for two photolytes with high affinity for the surface cooperative effects may occur. The methanol-oxalate system is quantitatively modeled by considering that oxalate forms surface complexes with different reactivity and a parallel pathway for hole transfer to -OH and adsorbed oxalate. In this case as well as for electrolytes containing methanol and salicylate photooxidation of methanol (with low affinity for the surface) via intermediates formed by reaction with trapped holes (- • OH) is partially or fully suppressed. For electrolytes containing oxalic and salicylic acids in which both components chemisorb on TiO 2 the photoelectrochemical response depends on preadsorption, the photooxidation pathways deviates those of single component systems, and there is remotion of salicylate adsorbed byproducts assigned to cooperative effects. |
| format |
JOUR |
| author |
Calvo, M.E. Candal, R.J. Bilmes, S.A. |
| author_facet |
Calvo, M.E. Candal, R.J. Bilmes, S.A. |
| author_sort |
Calvo, M.E. |
| title |
Photooxidation of organic mixtures on biased TiO 2 films |
| title_short |
Photooxidation of organic mixtures on biased TiO 2 films |
| title_full |
Photooxidation of organic mixtures on biased TiO 2 films |
| title_fullStr |
Photooxidation of organic mixtures on biased TiO 2 films |
| title_full_unstemmed |
Photooxidation of organic mixtures on biased TiO 2 films |
| title_sort |
photooxidation of organic mixtures on biased tio 2 films |
| url |
http://hdl.handle.net/20.500.12110/paper_0013936X_v35_n20_p4132_Calvo |
| work_keys_str_mv |
AT calvome photooxidationoforganicmixturesonbiasedtio2films AT candalrj photooxidationoforganicmixturesonbiasedtio2films AT bilmessa photooxidationoforganicmixturesonbiasedtio2films |
| _version_ |
1807315922950553600 |