A Molecular Silane-Derivatized Ru(II) Catalyst for Photoelectrochemical Water Oxidation

Lei Wu, Michael Eberhart, Animesh Nayak, M. Kyle Brennaman, Bing Shan, Thomas J. Meyer

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

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+ (RuP2+ 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.

Original languageEnglish (US)
Pages (from-to)15062-15069
Number of pages8
JournalJournal of the American Chemical Society
Volume140
Issue number44
DOIs
StatePublished - Nov 7 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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