Adsorption and Decomposition of Dimethyl Methylphosphonate on Y₂O₃Nanoparticles

Abstract

Experimental studies explore the adsorption and decomposition pathways of the nerve agent simulant, dimethyl methylphosphonate (DMMP), on Y2O3 nanoparticles with mean diameters of 6 and 2 nm. DMMP adsorption on Y2O3 was studied in an ultrahigh vacuum surface science instrument with X-ray photoelectron spectroscopy and reflection absorption infrared spectroscopy. Uptake probability measurements reveal an initial sticking probability near unity, while vibrational spectroscopy indicates that adsorbed DMMP dissociates via cleavage of a P−OCH3 bond to form a bridging O−P−O surface species. The extent of DMMP decomposition is found to increase as the particle size decreases, suggesting that edge, corner, and defect sites play a major role in the outcome of the gas−surface interaction.