Decomposition mechanism of dihydroxylammonium 5,5'-bis(tetrazole)-1,1'-diolate on Al(111) surface by periodic DFT calculation

The generalized gradient approximation (GGA) of density function theory (DFT) methods are employed to investigate the decomposition of TKX-50 molecule on the Al(111) surface. The calculation employs an Al supercell slab model and periodic boundary conditions. Five kinds of adsorption configurations for TKX-50 on Al surface are studied. The TKX-50 is adsorbed on Al surface to form the N–Al, O–Al and OH–Al bonds. The adsorption energies are in the range from –113.15 to –1334.40 kJ/mol. The activation energies of all configurations are in the range of 100.34–354.10 kJ/mol. The N1-N2 ruptures in V1 and N2-N3 ruptures in V2 takes place easily. The activation energies of these two bonds rupture (100.34 and 108.06 kJ/mol, respectively) are less than that of pure TKX-50 (161.58 and 215.99 kJ/mol). Al atoms promote the breaking of the tetrazole ring of TKX-50. The quantities of electron transfer from Al atoms to TKX-50 are in range of 1.42–4.90 e.