Efficient Photochemical Water Splitting by a Chemically Modified$n-TiO_2

Although n-type titanium dioxide (TiO2) is a promising substrate for photogeneration of hydrogen from water, most attempts at doping this material so that it absorbs light in the visible region of the solar spectrum have met with limited success. We synthesized a chemically modified n-type TiO2by co...

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Bibliographic Details
Published inScience (American Association for the Advancement of Science) Vol. 297; no. 5590; pp. 2243 - 2245
Main Authors Shahed U. M. Khan, Al-Shahry, Mofareh, Ingler, William B.
Format Journal Article
LanguageEnglish
Published American Association for the Advancement of Science 27.09.2002
Subjects
Electric current
Electrodes
Energy
Flames
Hydrogen
Light
Natural gas
Oxygen
Wavelengths
X ray film
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Summary:Although n-type titanium dioxide (TiO2) is a promising substrate for photogeneration of hydrogen from water, most attempts at doping this material so that it absorbs light in the visible region of the solar spectrum have met with limited success. We synthesized a chemically modified n-type TiO2by controlled combustion of Ti metal in a natural gas flame. This material, in which carbon substitutes for some of the lattice oxygen atoms, absorbs light at wavelengths below 535 nanometers and has a lower band-gap energy than rutile (2.32 versus 3.00 electron volts). At an applied potential of 0.3 volt, chemically modified n-type TiO2performs water splitting with a total conversion efficiency of 11% and a maximum photoconversion efficiency of 8.35% when illuminated at 40 milliwatts per square centimeter. The latter value compares favorably with a maximum photoconversion efficiency of 1% for n-type TiO2biased at 0.6 volt.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1075035