A Theoretical Investigation of the Catalytic Decomposition of Hydroxylamine Nitrate on Ir(110) Surface

Hydroxylamine nitrate (HAN) based propellant, with high energy performance and non-toxic, is regarded as an ideal propellant for monopropellant rocket engine. Density functional theory calculation was carried out to investigate the catalytic decomposition of HAN on Ir(1 1 0) surface. The optimized adsorption configurations and decomposition pathways of HAN on Ir(1 1 0) were calculated. Four different adsorption configurations and their decomposition pathways over Ir(1 1 0) have been found. The transformation of H from HNO3 to NH2OH happens in all adsorption configurations. In most situations, the decomposition of HAN starts with the scission of N-O bond in NH3OH+ group. NH, OH, H2O and NO2 are the decomposition product. Compared with the barrier energy of each elementary reaction, the scission of N-O bond in NO3- group is key to the decomposition rate of HAN. Among all products, NO2 and NH can be decomposed into N, O and H by scission of N-O bond and N-H bond.