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TiO 2 Photoelectrodes for Water Splitting: Carbon Doping by Flame Pyrolysis?
Author(s) -
Barnes P. R. F.,
Randeniyaly L. K.,
Murphy A. B.,
Gwan P. B.,
Plumb I. C.,
Glasscock J. A.,
Grey I. E.,
Li C.
Publication year - 2006
Publication title -
developments in chemical engineering and mineral processing
Language(s) - English
Resource type - Journals
eISSN - 1932-2143
pISSN - 0969-1855
DOI - 10.1002/apj.5500140105
Subject(s) - pyrolysis , materials science , photocatalysis , rutile , water splitting , titanium dioxide , titanium oxide , hydrogen , doping , carbon fibers , oxide , chemical engineering , band gap , titanium , inorganic chemistry , catalysis , chemistry , optoelectronics , composite material , organic chemistry , metallurgy , composite number , engineering
Titanium dioxide is often used as a photoelectrode material for water splitting, but its band gap is too wide to achieve high conversion efficiencies in sunlight. Flame oxidation (pyrolysis) of titanium sheet has been suggested as a method to produce carbon doped TiO 2 with a reduced band gap. In the present study, films were prepared using this and other thermal oxidation techniques and the photoelectrochemical water splitting efficiency of the resultant materials was examined using a xenon lamp. The oxide films were characterised physically, optically and electrochemically. Incident photon conversion efficiency measurements indicated no significant reduction in the band gap offilms prepared using a hydrocarbon flame compared to rutile TiO 2 . Furthermore, these films were found to have an efficiency comparable to that offilms produced in a carbon free flame (hydrogen/oxygen). The results suggest that flame pyrolysis may not ‘dope’ TiO, with carbon in the manner previously proposed. Any enhancement in photocatalytic eficiency resulting from the technique is likely to be due to the formation of non‐stoichiometric TiO 2 or titanium sub‐oxides.