A Molecular Silane-Derivatized Ru(II) Catalyst for Photoelectrochemical Water Oxidation
Photoanodes in dye-sensitized photoelectrosynthesis cells integrate molecular chromophore/catalyst assemblies on mesoporous n-type metal oxide electrodes for light-driven water oxidation. One limitation for sustainable photoanodes is the stability of chromophore/catalyst assembly on electrode surfac...
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Published in: | Journal of the American Chemical Society 2018-11, Vol.140 (44), p.15062-15069 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Photoanodes in dye-sensitized photoelectrosynthesis cells integrate molecular chromophore/catalyst assemblies on mesoporous n-type metal oxide electrodes for light-driven water oxidation. One limitation for sustainable photoanodes is the stability of chromophore/catalyst assembly on electrode surfaces for long periods. Progress has been made in stabilizing chromophores based on atomic layer deposition, polymer dip coating, C–C cross-coupling by electropolymerization, and silane surface binding, but little progress has been made on catalyst stabilization. We report here the silane-derivatized catalyst, Ru(bda)(L)2 (bda = 2,2′-bipyridine-6,6′-dicarboxylate, L = 4-(6-(triethoxysilyl)hexyl)pyridine), catalyst 1, which is stabilized on metal oxide electrode surfaces over an extended pH range. A surface stabilization study shows that it maintains its reactivity on the electrode surface toward electrochemical oxidation over a wide range of conditions. Its electrochemical stability on electrode surfaces has been systematically evaluated, and its role as a catalyst for water oxidation has been explored. On surfaces of mesoporous nanostructured core/shell SnO2/TiO2, with a TiO2 stabilized inner layer of the Ru(II) polypyridyl chromophore, [Ru(4,4′-(PO3H2)2bpy)(bpy)2]2+ (RuP 2+ ; bpy = 2,2′-bipyridine), highly efficient photoelectrochemical water oxidation catalysis occurs to produce O2 with a maximum efficiency of ∼1.25 mA/cm2. Long-term loss of catalytic activity occurs with time owing to catalyst loss from the electrode surface by axial ligand dissociation in the high oxidation states of the catalyst. |
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ISSN: | 0002-7863 1520-5126 |
DOI: | 10.1021/jacs.8b10132 |