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1589731 
Journal Article 
Water Splitting by Nanocrystalline TiO2 in a Complete Photoelectrochemical Cell Exhibits Efficiencies Limited by Charge Recombination 
Cowan, AJ; Tang, J; Leng, W; Durrant, JR; Klug, DR 
2010 
Yes 
Journal of Physical Chemistry C
ISSN: 1932-7447
EISSN: 1932-7455 
114 
9 
4208-4214 
WOS:000275045600072 
We report on the mechanism of water splitting by TiO2 in the
absence of chemical scavengers in a fully functional photoelectrochemical (PEC) cell. The
application of a positive potential to a nanocrystalline-TiO2 film is shown to lead to the
formation of long-lived holes which oxidize water on the milliseconds time scale. These first
time-resolved Studies of a nanocrystalline-TiO2 (nc-TiO2) film in a complete PEC cell also showed
that all of the long-lived photoholes go on to generate O-2, and that there are no major
branching inefficiencies in the catalysis itself, which appears to be operating at efficiencies
close to 100%. The overall quantum yield of oxygen production under pulsed illumination (355 nm)
was found to be similar to 8% at excitation densities of 4.4 photons per particle. Under all
conditions examined, electron-hole recombination was found to be the dominant loss pathway.