Abstract
Silatrane surface anchors are protected siloxanes that are known to bond firmly (from pH 2-11) to metal oxide electrodes under heating. However, these conditions are not always compatible with the other functionality present. A silatrane-containing porphyrin molecule and a silatrane-containing ruthenium complex have now been designed, synthesized and optimized conditions have been identified for surface binding. Two mild, roomerature surface binding methods were explored: binding with or without an acidic pretreatment; these methods were compared to the traditional, harsher binding conditions involving strong heating. We find that a preacidified electrode gave comparable surface loadings at room temperature compared to sensitization by using the previous strong heating method. This was also true on TiO 2 , SnO 2 , and nanoITO electrodes and thus may be generalizable. The new, milder binding methods also resulted in excellent aqueous and electrochemical stability from pH 2-11. Using a water-insoluble porphyrin with a silatrane anchor further increased the aqueous stability of the deposit, aided by the insolubility of the porphyrin. Finally, X-ray photoelectron spectroscopy (XPS) data confirmed for the first time that the triethanolamine released from the silatrane on deprotection/binding in turn binds to TiO 2 , SnO 2 , and nanoITO electrodes. This undesired triethanolamine deposit was easily removed from the surface by electrochemical voltage cycling or with an aqueous acidic wash for 1 h.
Original language | English |
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Pages (from-to) | 5602-5609 |
Number of pages | 8 |
Journal | ACS Applied Materials and Interfaces |
Volume | 11 |
Issue number | 6 |
DOIs | |
Publication status | Published - Feb 13 2019 |
Keywords
- metal oxides
- silatranes
- solar energy
- surface anchors
- tin oxide
- titanium dioxide
- water splitting
ASJC Scopus subject areas
- Materials Science(all)