Abstract
Ti-SBA-15 and Ti-MCM-41 were synthesized and evaluated as possible photocatalysts for the reduction of CO2, and for the photo-Kolbe decomposition of acetic acid. UV-Raman was used to study the adsorption of carbon dioxide, water, formic acid, and acetic acid over Ti-MCM-41 by monitoring the UV enhanced resonance peak of the totally symmetric stretching band of the grafted Ti species at 1,085 cm-1. Acetic and formic acid dissociate on Ti-SBA-15 and Ti-MCM-41 to form acetate and formate, respectively. The conjugate bases subsequently interact strongly with Ti sites. Water interacts with the Ti sites, while no change in the amplitude of the 1,085 cm-1 band is observed in the presence of CO2. Photocatalysis experiments indicate that these mesoporous silicalites are active in the photo-Kolbe decomposition of acetic acid. CO2 is formed by reaction of a hole with the acetate carboxylate groups. The methyl radical co-products react with a surface proton and an electron to form methane. No products resulting from the dimerization of methyl radicals are observed, presumably because of the highly dispersed active sites.
Original language | English |
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Pages (from-to) | 1057-1066 |
Number of pages | 10 |
Journal | Catalysis Letters |
Volume | 141 |
Issue number | 8 |
DOIs | |
Publication status | Published - Aug 2011 |
Keywords
- Mesoporous silicalites
- Photo-decomposition
- Photocatalysis
- Ti-MCM-41
- Ti-SBA-15
- Titanium grafted
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)