| AVS 62nd International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS+AS+EN-TuA |
| Session: | Mechanistic Insight of Surface Reactions: Catalysis, ALD, etc. - II |
| Presenter: | Ashley Head, Lawrence Berkeley National Laboratory (LBNL) |
| Authors: | A.R. Head, Lawrence Berkeley National Laboratory (LBNL) L. Trotochaud, Lawrence Berkeley National Laboratory (LBNL) Y. Yu, Lawrence Berkeley National Laboratory (LBNL) Z. Hicks, Johns Hopkins University X. Tang, Johns Hopkins University K. Bowen, Johns Hopkins University B. Eichhorn, University of Maryland, College Park H. Bluhm, LBNL |
| Correspondent: | Click to Email |
There is great interest in understanding the interaction between the nerve agent simulant dimethyl methyl phosphonate (DMMP) and metal oxide surfaces to further nerve agent filtration technology and decomposition methods. To this end, we have studied the room temperature adsorption of DMMP on MoO2 and MoO3 surfaces up to 30 mTorr using ambient pressure x-ray photoelectron spectroscopy (APXPS). On both surfaces, the majority of DMMP adsorbs intact, but differences in the behavior of DMMP on the two substrates are found upon heating. Two phosphorus species are seen on the MoO2 surface and three are seen on the MoO3; these species remain on both surfaces up to 450 ºC Additionally, carbon remains on the MoO2 at high temperatures but is removed from MoO3 by 420 ºC. The APXPS data were correlated with TPD measurements of DMMP adsorbed on MoO3 clusters on HOPG, a model system closer to real filtration materials. Methanol was found as the major decomposition product in addition to trace amounts of dimethyl ether. The easily reducible MoO3 is likely responsible for an oxidative cleavage of the P-CH3 bond on both the surface and nanoparticles. These studies highlight how APXPS coupled with TPD yields chemical information relevant to real-world applications.