Evolution of textural properties and performance of Ir/Al2O3 catalysts during hydrazine catalytic decomposition in a 2 N satellite thruster

Ir/Al2O3 catalysts with an approximate metal content of 30% in weight were prepared by incipient wetness methodology. Three alumina with different textural properties were chosen due to their different macro and mesoporosity. Catalysts were prepared through three consecutive impregnations and H2IrCl6 was used as a metallic precursor. They were characterized before and after the tests in a 2 N satellite thruster, according to specific surface area, volume and pore size distribution, and specific metallic area. Thrust performance stability, temperature and stagnation pressure in the chamber, and mass loss were analyzed. Catalyst's performance was then compared with that of the Shell 405 commercial catalyst.

► Performance in N2H4 decomposition was very similar for all catalysts employed.
► The area loss observed in catalyst C was probably due to loss of micro porosity.
► An apparent particle diameter increase was due to partial Ir occlusion in pores.
► Catalysts A and B presented smaller values for absolute mass loss in the thruster.
► Catalyst C degraded more since its absolute mass loss was more significant.