Abstract
Ammonium dinitramide (ADN, [NH4+][N(NO2)2-])-based energetic ionic liquid propellants (ADN-EILPs) are green and high-energy-density monopropellants. To expand their usage on a thruster system, this study investigates their catalytic ignition, which is a simple and most popular method. However, no detailed reports on the catalytic ignition of ADN-EILPs are available. Rapid decomposition of ADN-EILPs is necessary for their rapid ignition, which might involve reactions in liquid/condensed phases. This study screens effective catalysts that can be used for the ignition of a representative composition of ADN-EILPs by focusing on the thermal decomposition of the liquid/condensed phase of the ADN-EILP. By conducting a literature survey and by investigating the physical properties of the selected candidates, the catalyst candidates were narrowed down to platinum (Pt), rhodium (Rh), and iridium (Ir) for the decomposition of the ADN-EILP. Thermal analysis of a mixture of the ADN-EILP and catalyst candidates showed that Pt-, Rh-, and Ir-based catalysts can be considered as candidate catalysts for the decomposition of the ADN-EILP. The results showed that the catalysis mechanism is associated with the decomposition of monomethylamine nitrate or ammonium nitrate in the ADNEILP.
