Uptake of a Chemical Warfare Agent Simulant (DMMP) on TiO2: Reactive Adsorption and Active Site Poisoning

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• 作者：Dimitar A. Panayotov ; John R. Morris*
• 刊名：Langmuir
• 出版年：2009
• 出版时间：March 17, 2009
• 年：2009
• 卷：25
• 期：6
• 页码：3652-3658
• 全文大小：316K
• 年卷期：v.25,no.6(March 17, 2009)
• ISSN：1520-5827

文摘

Using Fourier transform infrared spectroscopy (FTIR) we studied the overall reaction pathways and ultimate fate of dimethyl methylphosphonate (DMMP), a chemical warfare agent simulant, on a commercial nanoparticulate (20 nm) titania material. Our data show that the initial uptake occurs through both molecular and reactive adsorption. Molecular adsorption is driven by hydrogen-bond formation to isolated hydroxyl groups. The reactive chemisorption appears to occur through interaction with both Lewis acid sites and active oxygen species present on the TiO₂ surface. The reactive sites are found to be poisoned quickly by oxidation products that include a strongly bound, nonvolatile phosphorus compound. Thermal reactivation of the TiO₂ in oxygen restores the physisorption capacity of the particles toward the DMMP, but the reactive adsorption pathway is nearly completely eliminated.