Abstract: A series of alumina- or silica-supported precious metal catalysts have been screened for catalytic decomposition of hydroxyl ammonium nitrate by the thermal analysis method. Ir/SiO2 exhibits the highest catalytic activity, on which 80% hydroxyl ammonium nitrate can be completely decomposed even at 20.7 ℃, manifesting its great potentials as an environmentally benign monopropellant. H2 chemisorption on Ir/SiO2 and Ir/Al2O3 suggests that a large particle size seems to be favorable for this reaction.

Key words: iridium, silica, supported catalyst, hydroxyl ammonium nitrate, catalytic decomposition, green propellant