TY - JOUR
T1 - Experimental study of dimethyl methylphosphonate decomposition over anatase TiO2
AU - Trubitsyn, Dmitry A.
AU - Vorontsov, Alexander V.
PY - 2005/11/24
Y1 - 2005/11/24
N2 - Removal from air and decomposition of dimethyl methylphosphonate (DMMP) over high surface area anatase TiO2 at ambient temperature have been quantitatively studied by employing Fourier transform infrared (FTIR) technique under static conditions. In the first scenario of air purification, DMMP underwent reactive adsorption that upon completion was followed by photocatalytic oxidation. DMMP was captured over the TiO2 surface at the speed of external diffusion. Hydrolysis of adsorbed DMMP led to methanol and methyl methylphosphonate (MMP). At low DMMP coverage quantity, it hydrolyzed completely with the formation of completely surface-bound methanol at 1% relative humidity (RH) and mostly gaseous methanol at 50% RH. Photocatalytic oxidation generated CO2 as the only carbonaceous gaseous product and bidentate formates as the intermediate surface product. At high DMMP coverage quantity, it was captured incompletely and hydrolyzed partially with CH 3OH in the gas phase only, 50% RH enhancing both processes. Photocatalytic oxidation generated gaseous HCOOH, CO, and CO2 and was incomplete due to catalyst deactivation by nonvolatile products. In the second scenario of air purification, DMMP underwent adsorption, hydrolysis, and photooxidation at the same time. It resulted in the quickest removal of DMMP from the gas phase and completion of oxidation in 30 min, suggesting this process for practical air decontamination. At least 0.8 nm2 of TiO2 surface per each DMMP molecule should be available for complete purification of air.
AB - Removal from air and decomposition of dimethyl methylphosphonate (DMMP) over high surface area anatase TiO2 at ambient temperature have been quantitatively studied by employing Fourier transform infrared (FTIR) technique under static conditions. In the first scenario of air purification, DMMP underwent reactive adsorption that upon completion was followed by photocatalytic oxidation. DMMP was captured over the TiO2 surface at the speed of external diffusion. Hydrolysis of adsorbed DMMP led to methanol and methyl methylphosphonate (MMP). At low DMMP coverage quantity, it hydrolyzed completely with the formation of completely surface-bound methanol at 1% relative humidity (RH) and mostly gaseous methanol at 50% RH. Photocatalytic oxidation generated CO2 as the only carbonaceous gaseous product and bidentate formates as the intermediate surface product. At high DMMP coverage quantity, it was captured incompletely and hydrolyzed partially with CH 3OH in the gas phase only, 50% RH enhancing both processes. Photocatalytic oxidation generated gaseous HCOOH, CO, and CO2 and was incomplete due to catalyst deactivation by nonvolatile products. In the second scenario of air purification, DMMP underwent adsorption, hydrolysis, and photooxidation at the same time. It resulted in the quickest removal of DMMP from the gas phase and completion of oxidation in 30 min, suggesting this process for practical air decontamination. At least 0.8 nm2 of TiO2 surface per each DMMP molecule should be available for complete purification of air.
UR - http://www.scopus.com/inward/record.url?scp=28944448385&partnerID=8YFLogxK
U2 - 10.1021/jp053793q
DO - 10.1021/jp053793q
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C2 - 16853843
AN - SCOPUS:28944448385
SN - 1520-6106
VL - 109
SP - 21884
EP - 21892
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 46
ER -