Insight into the adsorption and decomposition mechanism of MTNP on the Al (111) surface: A DFT study

By analyzing adsorption energy, charge transfer and electronic properties, the adsorption and decomposition mechanism of 1-methyl-3,4,5-trinitro-1H-pyrazole (MTNP) on the Al(1 1 1) surface was investigated based on density functional theory (DFT) with dispersion correction. Considering the adsorption sites on Al surface and the molecular orientation of MTNP, 17 configurations were examined. The results indicate that MTNP can undergo both chemisorption and physical adsorption on Al surface. In the case of chemisorption, the N-O bond breakage of the nitro group in MTNP is the main decomposition mechanism. The dissociated oxygen atoms form Al-O bonds with nearby Al atoms, and the free radical obtained after oxygen elimination is also adsorbed to the surface by forming Al-O and Al-N bonds. When the methyl group of MTNP points vertically downward to the Al (111) surface, physical adsorption occurs due to the repulsive effect of Al surface to methyl group.