Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways
Abstract Photoelectrochemical oxidation of methylene blue is investigated, with particular focus on the difference in kinetics and thermodynamics of decoloration and mineralization employing photoinduced absorption spectroscopy. Hematite and titania photoanodes are used for the comparison of both re...
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| Format: | Article |
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Wiley
2023-03-01
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| Series: | Advanced Science |
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| Online Access: | https://doi.org/10.1002/advs.202206685 |
| _version_ | 1797860837431443456 |
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| author | Xinyue Guo Zixuan Ma Yuling Yuan Yan Kang Hong Xu Zhiping Mao Yimeng Ma |
| author_facet | Xinyue Guo Zixuan Ma Yuling Yuan Yan Kang Hong Xu Zhiping Mao Yimeng Ma |
| author_sort | Xinyue Guo |
| collection | DOAJ |
| description | Abstract Photoelectrochemical oxidation of methylene blue is investigated, with particular focus on the difference in kinetics and thermodynamics of decoloration and mineralization employing photoinduced absorption spectroscopy. Hematite and titania photoanodes are used for the comparison of both reactions, which is determined to be associated with the depth of the valence band (3.2 vs 2.5 V for titania and hematite, respectively). Methylene blue is mineralized by the titania photoanode, however it is only oxidized to small fragments by hematite. Such difference is related to the valence band potential that provides the thermodynamic driving force for photogenerated holes in both materials. In addition, the kinetic competition of water oxidation is found to occur on titania by controlling the pH of the electrolyte. In the pH 14 electrolyte, mineralization of methylene blue is suppressed due to the faster and dominant kinetics of water oxidation, in contrast to the complete mineralization in the near neutral electrolyte where water oxidation kinetics are modest. These results clearly address the importance considering both thermodynamic and kinetic challenges of methylene blue oxidation, which has been thought to be an easy molecule to oxidize, as the model reaction in the application of photo(electro)catalysis using metal oxides. |
| first_indexed | 2024-04-09T21:53:25Z |
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| id | doaj.art-ae4f4fc5ab2940e8a77c90e1cf75e099 |
| institution | Directory Open Access Journal |
| issn | 2198-3844 |
| language | English |
| last_indexed | 2024-04-09T21:53:25Z |
| publishDate | 2023-03-01 |
| publisher | Wiley |
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| series | Advanced Science |
| spelling | doaj.art-ae4f4fc5ab2940e8a77c90e1cf75e0992023-03-24T12:30:04ZengWileyAdvanced Science2198-38442023-03-01109n/an/a10.1002/advs.202206685Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction PathwaysXinyue Guo0Zixuan Ma1Yuling Yuan2Yan Kang3Hong Xu4Zhiping Mao5Yimeng Ma6Key Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaKey Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaKey Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaShanghai Jahwa United Co., Ltd. Shanghai 200082 ChinaKey Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaKey Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaKey Laboratory of Science and Technology of Eco‐Textile, Ministry of Education College of Chemistry and Chemical Engineering Donghua University Shanghai 201620 ChinaAbstract Photoelectrochemical oxidation of methylene blue is investigated, with particular focus on the difference in kinetics and thermodynamics of decoloration and mineralization employing photoinduced absorption spectroscopy. Hematite and titania photoanodes are used for the comparison of both reactions, which is determined to be associated with the depth of the valence band (3.2 vs 2.5 V for titania and hematite, respectively). Methylene blue is mineralized by the titania photoanode, however it is only oxidized to small fragments by hematite. Such difference is related to the valence band potential that provides the thermodynamic driving force for photogenerated holes in both materials. In addition, the kinetic competition of water oxidation is found to occur on titania by controlling the pH of the electrolyte. In the pH 14 electrolyte, mineralization of methylene blue is suppressed due to the faster and dominant kinetics of water oxidation, in contrast to the complete mineralization in the near neutral electrolyte where water oxidation kinetics are modest. These results clearly address the importance considering both thermodynamic and kinetic challenges of methylene blue oxidation, which has been thought to be an easy molecule to oxidize, as the model reaction in the application of photo(electro)catalysis using metal oxides.https://doi.org/10.1002/advs.202206685hematitemineralizationphotoinduced absorption spectroscopytitaniavalence band potential |
| spellingShingle | Xinyue Guo Zixuan Ma Yuling Yuan Yan Kang Hong Xu Zhiping Mao Yimeng Ma Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways Advanced Science hematite mineralization photoinduced absorption spectroscopy titania valence band potential |
| title | Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways |
| title_full | Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways |
| title_fullStr | Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways |
| title_full_unstemmed | Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways |
| title_short | Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways |
| title_sort | photoinduced absorption spectroscopy of photoelectrocatalytic methylene blue oxidation on titania and hematite the thermodynamic and kinetic impacts on reaction pathways |
| topic | hematite mineralization photoinduced absorption spectroscopy titania valence band potential |
| url | https://doi.org/10.1002/advs.202206685 |
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