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Selective Photocatalytic Oxidation of Alcohols to Aldehydes in Water by TiO 2 Partially Coated with WO 3
Author(s) -
Tsukamoto Daijiro,
Ikeda Makoto,
Shiraishi Yasuhiro,
Hara Takayoshi,
Ichikuni Nobuyuki,
Tanaka Shunsuke,
Hirai Takayuki
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100166
Subject(s) - aldehyde , catalysis , photocatalysis , selectivity , calcination , tungstic acid , decomposition , chemistry , inorganic chemistry , alcohol oxidation , adsorption , heterogeneous catalysis , photochemistry , organic chemistry
Semiconductor TiO 2 particles loaded with WO 3 (WO 3 /TiO 2 ), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at λ >350 nm. The WO 3 /TiO 2 catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO 2 . In particular, a catalyst loading 7.6 wt % WO 3 led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO 2 surface of the catalyst, which is active for oxidation, is partially coated by the WO 3 layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO 2 surface. This suppresses subsequent decomposition of the aldehyde on the TiO 2 surface and results in high aldehyde selectivity. The WO 3 /TiO 2 catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.