Aluminum Oxide–Supported Manganese Oxide Catalyst for a 98% Hydrogen Peroxide Thruster

Silica-doped alumina–supported catalyst, containing manganese oxides, doped with cobalt oxide, was prepared in situ by wet impregnation, vacuum drying, and calcination at 700°C. Potassium permanganate and cobalt nitrate were used as precursors and thermally decomposed. The active phase content was determined by simple mass measurement. Subsequently, scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and physical adsorption by Brunauer-Emmet-Teller tests have been carried out to determine the morphology, chemical and phase composition, and specific surface area. The catalyst was subjected to the real-environment testing in a packed catalyst bed of a small rocket engine; 98% hydrogen peroxide was applied as propellant. At the design stage of a packed catalyst, it was assumed that a bed loading varied from 24.5 to 30 kg/(s⋅m2). The total propellant throughput was 5.43 kg. After the test campaign, the microscopic observation of the structure and physisorption were repeated to describe changes in the structure of the active phase. Test parameters and their change in time were analyzed. The influence of structural and chemical changes between fresh and tested catalysts was taken into consideration. The quality of pure carrier and manganese oxides catalyst, for decomposition of 98% hydrogen peroxide, was investigated. A comparison of performance with alumina-supported platinum catalyst was presented and discussed.