Partial photocatalytic oxidations of 3-pyridinemethanol and 3-picoline by TiO2 prepared in HCl, HNO3 and H2SO4 at different temperatures
| Autor: | Sıdıka Çetinkaya, Sedat Yurdakal |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Anatase
Chemistry Brookite 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0104 chemical sciences chemistry.chemical_compound Desorption visual_art Photocatalysis visual_art.visual_art_medium Picoline Partial oxidation 0210 nano-technology Selectivity Nuclear chemistry |
| Zdroj: | Catalysis Today. 380:237-247 |
| ISSN: | 0920-5861 |
| Popis: | Home prepared TiO2 photocatalysts were prepared from TiCl4 precursor in the absence and presence of HCl (1-6 M), HNO3 (1 M) or H2SO4 (1 M) at room temperature (RT), 60 or 100 degrees C. The TiO2 catalysts were characterised by XRD, BET, SEM and TGA techniques. TiO2 catalyst could not form at low temperature (up to 60 degrees C) in the presence of H2SO4. Just rutile phase was obtained for all TiO2 samples prepared at RT and 60 degrees C in HCl or HNO3. At 100 degrees C mainly both brookite and rutile phases were obtained in the presence of HCl or HNO3, whilst mainly anatase phase appeared in the presence of H2SO4. Nanorod structured TiO2 was formed in the presence of 1 M HCl or HNO3 at RT and 60 degrees C. The prepared TiO2 catalysts were used for partial oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 in water under UVA irradiation. Moreover, photocatalytic oxidation of 3picoline, precursor of 3-pyridinemethanol, was also performed, but much lower product selectivity values were obtained with respect to 3-pyridinemethanol oxidation. However, selective 3-picoline oxidation could be performed at pH 2 with low activity. Degussa P25 was used for comparison and almost all home prepared catalysts showed a higher selectivity, but they showed to be less active than Degussa P25. The high selectivity of the home prepared samples was not due to the type of TiO2 phase, but mainly to the hydrophilicity of the TiO2 surface which allowed desorption of valuable products instead of their over-oxidation. |
| Databáze: | OpenAIRE |
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