Synthesis of Iron-Porphyrins Immobilized onto Titanium Dioxide and Their Catalytic Activities on the Oxidation Reactions
Date Issued
2009
Date
2009
Author(s)
Liang, Chia-Jung
Abstract
Using porphyrin to reinforce photocatalytic capability of TiO2 has always been a target for chemists to work with. Recent research of TPP indicates that the anchoring groups at meta or para position can affect the binding geometries of the porphyrins onto TiO2, the amount of binding porphyrins, the electron transfer property and the catalytic activity of oxidation reactions. Thus, in this thesis, we synthesize three kinds of iron or zinc tetraphenylporphyrins with carboxyl substitunents at the meta or para position of the phenyl groups on the TPP and further immobilized onto the surface of titanium dioxide. In photodegradation of phenolic compound, the meta position porphyrin-TiO2 catalyst was able to carry out the degradation over 90% of 4-Nitrophenol under 5 hours illumination of visible light. Other phenols can also undergo degradation by using this catalyst. Compare to non-modified TiO2 catalyst, only 35% of 4-nitrophenol was degraded under the same conditions. Without illumination, no photo-degradation was observed, suggest that modification of porphyrin on TiO2 indeed promote the photocatalytic ability. This system can also be used to catalyze the oxidation of ethylbenzene into acetophenone with molecular oxygen in the presence of an initiator NHPI. The combination of iron-pyridine or viologen and porphyrins immobilized onto TiO2 or change the axial ligand to pyridine can further improve the yield of the oxidation. Under optimal conditions, oxidation of ethylbenzene into acetophenone under 1 atm O2 and 1 mol% NHPI reach to 64% yield.
Subjects
porphyrin
oxidation
tio2
Type
thesis
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