DFT investigation on the adsorption of munition compounds on α-Fe2O3: similarity and differences with α-Al2O3

Abstract

Arid environments have long been a testing and training ground for novel munitions. However, these activities leave behind unknown quantities of munition residues with unknown impact on local flora and fauna. In particular, arid soil contains Lewis acidic metal oxides which bind and catalyze the electron rich substituent groups commonly found in munition compounds, although the exact mechanisms are poorly understood. The current study remedies this lack of knowledge by utilizing density functional theory (DFT) to explore various orientations of four important munition compounds on the α-Fe₂O₃(0001) and α-Al₂O₃(0001) surfaces. Our findings reveal that while α-Fe₂O₃ binds the munition compounds more strongly than α-Al₂O₃, all four compounds experienced elongation of their nitro (–NO₂) groups, indicating their susceptibility towards degradation on these surfaces.