Specific properties on TiO2 photocatalysis to decompose isopropyl methylphosphonofluoridate and dimethyl methylphosphonate in Gas Phase

The specific differences on TiO2 photocatalytic decomposition rates of vaporized isopropyl methylphosphonofluoridate, sarin (GB), rGB as a real Chemical Warfare Agent (CWA) and vaporized dimethyl methylphosphonate (DMMP), rDMMP as CWA simulant in gas phase have been investigated by Gas chromatography/mass spectrometry (GC/MS) analysis in ambient. The concentration of GB molecules adsorbed at the surface of TiO2 in the dark, CGB, was 28 times larger than CDMMP in the dark. The rGB was then 3.3 times faster than the rDMMP. The results were explained by taking into account faster hydrolysis of GB molecules at the surface of TiO2 and the larger diffusion constant of GB in the gas phase than DMMP molecules. The effect of F− adsorption at the surface of TiO2 as fluoridated surface on the TiO2 photocatalysis was also studied.