Photoelectrochemical oxidation of anions by WO_3 in aqueous and nonaqueous electrolytes
Abstract
The behavior of WO_3 photoanodes has been investigated in contact with a combination of four anions (Cl−, CH_3SO_3−, HSO_4−, and ClO_4−) and three solvents (water, acetonitrile, and propylene carbonate), to elucidate the role of the semiconductor surface, the electrolyte, and redox kinetics on the current density vs. potential properties of n-type WO_3. In 1.0 M aqueous strong acids, although the flat-band potential (E_(fb)) of WO_3 was dominated by electrochemical intercalation of protons into WO_3, the nature of the electrolyte influenced the onset potential (E_(on)) of the anodic photocurrent. In aprotic solvents, the electrolyte anion shifted both E_(fb) and E_(on), but did not significantly alter the overall profile of the voltammetric data. For 0.50 M tetra(n-butyl)ammonium perchlorate in propylene carbonate, the internal quantum yield exceeded unity at excitation wavelengths of 300–390 nm, indicative of current doubling. A regenerative photoelectrochemical cell based on the reversible redox couple B_(10)Br_(10)^(˙−/2−) in acetonitrile, with a solution potential of 1.7 V vs. the normal hydrogen electrode, exhibited an open-circuit photovoltage of 1.32 V under 100 mW cm^(−2) of simulated Air Mass 1.5 global illumination.
Additional Information
© 2013 The Royal Society of Chemistry. Received 1st March 2013; Accepted 18th June 2013. First published online 18 Jun 2013. We acknowledge the National Science Foundation (NSF) Powering the Planet Center for Chemical Innovation (CCI-Solar), Grants CHE-0802907 and CHE-0947829, and the Molecular Materials Research Center of the Beckman Institute at the California Institute of Technology, for support. QM acknowledges Dr Elizabeth A. Santori for assistance with the spectral response experiments, and the NSF for support as a CCI-Solar Postdoctoral Fellow.Attached Files
Published - c3ee40712h.pdf
Supplemental Material - c3ee40712h_si.pdf
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Additional details
- Eprint ID
- 41099
- Resolver ID
- CaltechAUTHORS:20130905-093517424
- NSF
- CHE-0802907
- NSF
- CHE-0947829
- Caltech Beckman Institute
- NSF Postdoctoral Fellowship
- Created
-
2013-09-16Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- CCI Solar Fuels