Titanium dioxide photocatalysis to decompose isopropyl methylphosphonofluoridate (GB) in gas phase

The adsorption and photocatalytic degradation of nerve agent, isopropyl methylphosphonofluoridate, Sarin (GB) as a real Chemical Warfare Agent (CWA) on powdery Titanium dioxide (TiO2) film have been investigated using Gas chromatography/mass spectrometry (GC/MS) analysis in ambient atmosphere. We found that the ability to decontaminate GB molecules on TiO2 photocatalyst can be estimated to be 42 molecules/nm2, indicating that 1 g of TiO2 photocatalyst can decontaminate 3.4 mmol of GB molecules as the limitation value to maintain the photocatalytic activity. We also elucidated a plausible photocatalytic decontamination mechanism of GB at the surface of TiO2 photocatalyst on the basis of the results obtained in this study.

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► Sarin (GB) quickly adsorbed at surface of TiO2 and was decomposed by TiO2 photocatalysis.
► Decontamination of vaporized GB was then strongly controlled by adsorption rate.
► The ability to decontaminate GB molecules on TiO2 photocatalyst can be estimated to be 42 molecules/nm2 which correspond to 17 layers/nm2.
► Organic solvent which is coexistent with GB affects the TiO2 photocatalytic decontamination rate, such as adsorption and decomposition.