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Binary aqueous HAN (hydroxylammonium nitrate NH 3 OHNO 3 ) of different concentrations (20, 60, 83 wt-%) have been thermally and catalytically decomposed. The catalysts were prepared by impregnation of pure or doped supports (alumina, zirconia, barium, magnesium or zirconium aluminate) with monometallic or bimetallic active phases (noble and non-noble metals). The evaluation of the catalysts was carried out using a thermal analysis apparatus and a batch constant volume reactor.The thermal decomposition starts only when the water has been quantitatively removed and the onset temperature was 115 °C for the 83 % solution using the batch reactor. In the presence of a support alone, a catalytic effect is evidenced for the alumina and silica-doped alumina by a decrease of the decomposition temperature, due to the acidity of the surface; on the other hand, doping with barium leads to an inhibiting effect. The presence of an adequate active phase leads to a further drop of the onset temperature (< 40 °C), disclosing that the decomposition can be triggered at low temperature in the presence of water; the rate is one order of magnitude higher by comparison with the thermal decomposition. The evaluation of other active phases leads to various results; iridium supported on alumina displays a fair activity.

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