Details
| Original language | English |
|---|---|
| Pages (from-to) | 102-110 |
| Number of pages | 9 |
| Journal | Catalysis today |
| Volume | 225 |
| Publication status | Published - 15 Apr 2014 |
Abstract
Pyrochlore bismuth titanate (Bi 2-xTi 0.75x)Ti 2O 7 was prepared by an aqueous sol-gel method and annealed at different temperatures. Non-stoichiometry was obtained by adjusting the Ti/Bi ratio during synthesis. Additionally the two bismuth titanate phases Bi 4Ti 3O 12 and Bi 2Ti 4O 11 were synthesized. The materials were characterized by X-ray diffraction and UV-vis reflectance spectroscopy. Photocatalytic hydrogen production was tested in the presence of methanol as sacrificial agent after loading the bismuth titanates with nanoparticles of platinum acting as co-catalysts. It was found that stoichiometric Bi 2Ti 2O 7 being completely inactive could be turned into a good photocatalyst by increasing the Ti/Bi ratio to 1.50 corresponding to (Bi 1.55Ti 0.33)Ti 2O 7 still crystallizing in a pure pyrochlore phase. The increase in activity is supposed to derive from an optimization of the TiO 6-octahedral geometry due to the generation of bismuth and oxygen vacancies in the lattice. If platinum is applied as co-catalyst on (Bi 2-xTi 0.75x)Ti 2O 7 samples, stability issues occur during photocatalysis, which are suppressed by coating the platinum particles with a Cr 2O 3 shell.
Keywords
- Bismuth titanate, Non-stoichiometry, Photocatalytic hydrogen production, Pyrochlore, Stability
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- General Chemistry
Sustainable Development Goals
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In: Catalysis today, Vol. 225, 15.04.2014, p. 102-110.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Photocatalytic hydrogen production with non-stoichiometric pyrochlore bismuth titanate
AU - Merka, O.
AU - Bahnemann, D.W.
AU - Wark, M.
N1 - Funding information: The authors thank Prof. Dr. J. Caro (Institut für Physikalische Chemie und Elektrochemie, Leibniz Universität Hannover) for providing laboratory space and the X-ray diffractometer. Financial support by the Deutsche Forschungsgemeinschaft (DFG) ( WA 1116/18-1 ) is gratefully acknowledged.
PY - 2014/4/15
Y1 - 2014/4/15
N2 - Pyrochlore bismuth titanate (Bi 2-xTi 0.75x)Ti 2O 7 was prepared by an aqueous sol-gel method and annealed at different temperatures. Non-stoichiometry was obtained by adjusting the Ti/Bi ratio during synthesis. Additionally the two bismuth titanate phases Bi 4Ti 3O 12 and Bi 2Ti 4O 11 were synthesized. The materials were characterized by X-ray diffraction and UV-vis reflectance spectroscopy. Photocatalytic hydrogen production was tested in the presence of methanol as sacrificial agent after loading the bismuth titanates with nanoparticles of platinum acting as co-catalysts. It was found that stoichiometric Bi 2Ti 2O 7 being completely inactive could be turned into a good photocatalyst by increasing the Ti/Bi ratio to 1.50 corresponding to (Bi 1.55Ti 0.33)Ti 2O 7 still crystallizing in a pure pyrochlore phase. The increase in activity is supposed to derive from an optimization of the TiO 6-octahedral geometry due to the generation of bismuth and oxygen vacancies in the lattice. If platinum is applied as co-catalyst on (Bi 2-xTi 0.75x)Ti 2O 7 samples, stability issues occur during photocatalysis, which are suppressed by coating the platinum particles with a Cr 2O 3 shell.
AB - Pyrochlore bismuth titanate (Bi 2-xTi 0.75x)Ti 2O 7 was prepared by an aqueous sol-gel method and annealed at different temperatures. Non-stoichiometry was obtained by adjusting the Ti/Bi ratio during synthesis. Additionally the two bismuth titanate phases Bi 4Ti 3O 12 and Bi 2Ti 4O 11 were synthesized. The materials were characterized by X-ray diffraction and UV-vis reflectance spectroscopy. Photocatalytic hydrogen production was tested in the presence of methanol as sacrificial agent after loading the bismuth titanates with nanoparticles of platinum acting as co-catalysts. It was found that stoichiometric Bi 2Ti 2O 7 being completely inactive could be turned into a good photocatalyst by increasing the Ti/Bi ratio to 1.50 corresponding to (Bi 1.55Ti 0.33)Ti 2O 7 still crystallizing in a pure pyrochlore phase. The increase in activity is supposed to derive from an optimization of the TiO 6-octahedral geometry due to the generation of bismuth and oxygen vacancies in the lattice. If platinum is applied as co-catalyst on (Bi 2-xTi 0.75x)Ti 2O 7 samples, stability issues occur during photocatalysis, which are suppressed by coating the platinum particles with a Cr 2O 3 shell.
KW - Bismuth titanate
KW - Non-stoichiometry
KW - Photocatalytic hydrogen production
KW - Pyrochlore
KW - Stability
UR - http://www.scopus.com/inward/record.url?scp=84894100924&partnerID=8YFLogxK
U2 - 10.1016/j.cattod.2013.09.009
DO - 10.1016/j.cattod.2013.09.009
M3 - Article
VL - 225
SP - 102
EP - 110
JO - Catalysis today
JF - Catalysis today
SN - 0920-5861
ER -