The adsorption and photocatalytic degradation of nerve agent, isopropyl methylphosphonofluoridate, Sarin (GB) on powdery TiO 2 film has been investigated using attenuated total reflection-infrared Fourier transform spectroscopy (ATR-FTIR) in ambient atmosphere. Producing innocuous isopropyl methylphosphonic acid as a consequence of GB adsorption at the surface of TiO 2 indicates that powdery TiO 2 film is effective to hydrolyze GB. The adsorbed GB and IMPA were quickly decomposed by TiO 2 photocatalysis to give isopropanol, acetone, formate, and methylphosphonic acid, and finally completely mineralized to phosphoric acid, water, and carbon dioxide. We also elucidated a plausible adsorption structure and photocatalytic decomposition mechanism of GB at the surface of TiO 2 photocatalyst.

A peroxo titanic acid (PTA) solution has been prepared by mixing titanic acid wet gel and hydrogen peroxide solution. The PTA solution was a neutral, transparent, stable liquid. The PTA crystallized to form an anatase phase after calcination at a temperature above 250. When the PTA solution was autoclaved at a temperature above 100 for 6h, it changed to a sol containing anatase crystals less than 20nm in diameter. Aggregation occurred after autoclaving at a temperature above 120. When the PTA solution was heated to 100, it was translucent and stable in spite of containing ultrafine anatase crystals (9nm in diameter). It was deduced that the surfaces of anatase crystals are modified by the peroxo groups.

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