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Title: Visible photoelectrochemical water splitting into H 2 and O 2 in a dye-sensitized photoelectrosynthesis cell

A hybrid strategy for solar water splitting is exploited here based on a dye-sensitized photoelectrosynthesis cell (DSPEC) with a mesoporous SnO 2/TiO 2 core/shell nanostructured electrode derivatized with a surface-bound Ru(II) polypyridyl-based chromophore–catalyst assembly. The assembly, [(4,4’-(PO 3H 2) 2bpy) 2Ru(4-Mebpy-4’-bimpy)Ru(tpy)(OH 2)] 4+ ([RuaII-RubII-OH 2] 4+, combines both a light absorber and a water oxidation catalyst in a single molecule. It was attached to the TiO 2 shell by phosphonate-surface oxide binding. The oxide-bound assembly was further stabilized on the surface by atomic layer deposition (ALD) of either Al 2O 3 or TiO 2 overlayers. Illumination of the resulting fluorine-doped tin oxide (FTO)|SnO 2/TiO 2|-[Ru a II-Ru b II-OH 2] 4+(Al 2O 3 or TiO 2) photoanodes in photoelectrochemical cells with a Pt cathode and a small applied bias resulted in visible-light water splitting as shown by direct measurements of both evolved H 2 and O 2. The performance of the resulting DSPECs varies with shell thickness and the nature and extent of the oxide overlayer. Use of the SnO 2/TiO 2 core/shell compared with nanoITO/TiO 2 with the same assembly results in photocurrent enhancements of ~5. In conclusion, systematic variations in shell thickness and ALD overlayer lead to photocurrentmore » densities as high as 1.97 mA/cm 2 with 445-nm, ~90-mW/cm 2 illumination in a phosphate buffer at pH 7.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry
  2. Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0001011
Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 19; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Energy Frontier Research Centers (EFRC). Center for Solar Fuels (UNC EFRC)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
UNC partners with University of North Carolina (lead); Duke University; University of Florida; Georgia Institute of Technology; University; North Carolina Central University; Research Triangle Institute
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (homogeneous), catalysis (heterogeneous), solar (photovoltaic), solar (fuels), photosynthesis (natural and artificial), hydrogen and fuel cells, electrodes - solar, charge transport, materials and chemistry by design, synthesis (novel materials), synthesis (self-assembly)
OSTI Identifier:
1210802