Catalytic decomposition of propellant N 2 O Over Ir/Al 2 O 3 catalyst

N 2 O, as a green propellant alternative to N 2 H 4 , shows potential application in satellite propulsion system. The state of Ir species and the reaction behaviors on Ir/Al 2 O 3 in the oxidative environment during N 2 O decomposition were identified here. Two types of Ir sites existed in this catalyst and affected the process of N 2 O decomposition. The strong Ir sites facilitated the dissociative adsorption of N 2 O to form N 2 and adsorbed O atoms with adsorption heat of as high as 281 kJ/mol, which promoted the desorption of adsorbed O atoms and favored the self‐sustaining decomposition of N 2 O by raising the catalyst bed temperature. The other Ir sites interacted weakly with O atoms but facilitated their combination to form O 2 . The Ir/Al 2 O 3 catalyst then exhibited an excellent performance in initiating the decomposition of N 2 O at low temperature of 200°C and good stability in 0.1 N microthruster for orbit adjustment and attitude control of satellite. © 2016 American Institute of Chemical Engineers AIChE J , 62: 3973–3981, 2016