Catalytic decomposition of energetic compounds - Influence of catalyst shape and ceramic substrate

Catalytic decomposition of energetic compounds is used for different purposes like propulsion application (launcher, satellites and missiles) and gas generator (e.g. rescue systems). The energetic liquids (H 2O2, N 2H4, ionic liquids, N 2O, …) are decomposed on catalytic beds which must present very good thermal and mechanical properties to resist frequent thermal shocks and high flow rates. Compared to conventional alumina-based supports developed specifically for this application about 30 years ago (extrudates, pellets, spheres), honeycomb monolith catalysts show many advantages: (i) lower pressure drop, (ii) better thermal shock and attrition resistance, (iii) uniform flow distribution and mass/heat transfer conditions, (iv) shorter diffusion length, and (v) large heritage from cleaning of car exhaust gases. Therefore, monolithic reactors represent very attractive alternatives to traditional systems with the future ability to develop chemical micro-propulsion systems. These new monolith applications demand a careful control of the substrate chemical nature, the surface impregnation by the thin porous wash-coat layer and the impregnation of this layer by the active phase precursor. An overview is given and two applications to the decomposition of hydrogen peroxide and ionic liquid solutions are presented and discussed.