The TiO2–Catechol Complex: Coupling Type II Sensitization with Efficient Catalysis of Water Oxidation |
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| Authors: | Zion Tachan Idan Hod Arie Zaban |
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| Affiliation: | Chemistry Department, Bar‐Ilan University, Ramat‐Gan, Israel |
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| Abstract: | Two main requirements must be fulfilled in order to construct an efficient TiO2‐based photo‐electrochemical water splitting cell. One is the expansion of the cell's spectral response, usually by the attachment of a sensitizing dye monolayer on the surface of the TiO2. The second involves the incorporation of a water oxidation catalyst that reduces the overpotential for the oxygen evolution reaction. These requirements are often achieved by the co‐adsorption of both the dye and the catalyst on the TiO2, or by a covalent attachment of the catalyst to the dye molecule. Here, the possibility to use a single material that acts as a sensitizer and a catalyst is presented. The use of a catechol molecule to form a type II charge transfer complex with TiO2 widens the absorption of the system into the visible region. The TiO2‐catechol complex is highly catalytic toward the oxidation of water to oxygen, reducing the electrocatalytic reaction overpotential by 500 mV compared to bare TiO2. A suggested catalytic mechanism for the water oxidation reaction is described. This methodology opens a new path for type II charge transfer complexes to be utilized as catalysts/light absorbers in water splitting systems based on TiO2 or other metal oxides. |
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| Keywords: | water splitting catalysis oxygen evolution reactions photoelectrochemistry |
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