Issue 38, 2022

Oxidative decomposition of dimethyl methylphosphonate on rutile TiO2(110): the role of oxygen vacancies

Abstract

The decomposition of dimethyl methylphosphonate (DMMP, (CH3O)2P(O)(CH3)), a simulant to the toxic nerve agent Sarin, on the rutile TiO2(110) surface has been studied with temperature programmed desorption (TPD) and density functional theory (DFT) calculations. The reactivity of the TiO2(110) surface for DMMP decomposition is shown to be low, with mainly molecular desorption and only a small fraction of methanol and formaldehyde decomposition products seen from TPD at around 650 K. In addition, this amount of products is similar to the number of O vacancies on the surface. DFT calculations show that O vacancies are key for P–OCH3 bond cleavage of DMMP, lowering the barrier by 0.7 eV and enabling the reactive process to occur at around 600 K. This is explained by the closer position of DMMP with respect to the surface in the presence of O vacancies. Calculations show that the produced methoxy groups can transform into gas phase formaldehyde and methanol at the considered temperature (600 K), in agreement with experiments. O–C bond cleavage of DMMP is also a viable pathway at such a high temperature (600 K) for DMMP decomposition on r-TiO2, even in the absence of O vacancies, but the formation of a gas phase product is energetically unfavorable. O vacancies hence are the active sites for decomposition of DMMP into gas phase products on r-TiO2(110).

Graphical abstract: Oxidative decomposition of dimethyl methylphosphonate on rutile TiO2(110): the role of oxygen vacancies

Supplementary files

Article information

Article type
Paper
Submitted
17 May 2022
Accepted
04 Sep 2022
First published
07 Sep 2022

Phys. Chem. Chem. Phys., 2022,24, 23402-23419

Author version available

Oxidative decomposition of dimethyl methylphosphonate on rutile TiO2(110): the role of oxygen vacancies

C. Tesvara, C. Walenta and P. Sautet, Phys. Chem. Chem. Phys., 2022, 24, 23402 DOI: 10.1039/D2CP02246J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements