Catalytic decomposition mechanism of aqueous ammonium dinitramide solution elucidated by thermal and spectroscopic methods

[Display omitted] •Ammonium dinitramide (ADN) is environmentally benign, energetic, oxygen rich molecule.•Condensed phase decomposition of ADN water solution studied using TG-FTIR technique.•Addition of CuO nanocatalyst changes thermal decomposition pathway of ADN solution.•Nanocatalyst presence during decomposition leads to formation of higher amount of NO2.•Ratios of IR transmittance values of N2O to NO2 confirmed increased amount of NO2. Ammonium dinitramide (ADN) is a green, energetic and oxygen rich molecule, developed to replace the commonly used oxidizer ammonium perchlorate (AP). On combustion ADN produces relatively environmental-friendly species such as H2O, NO2, N2O, NO etc., compared to HCl, Cl2, CO2, CO, H2, H2O, N2 and highly reactive chlorine species produced by AP combustion. The ADN synthesized in our laboratory was dissolved in deionized water to prepare aqueous ADN solutions (aq. ADN). The thermal decomposition of solid ADN and aq. ADN were studied and the products of decomposition are identified using a thermogravimetric analyser hyphenated with a FTIR instrument. Nano CuO catalyst was synthesized and aq. ADN was decomposed over the nanocatalyst and the catalytic decomposition mechanism is also elucidated. The study shows that, the condensed phase decomposition of aq. ADN is influenced by the CuO nanocatalyst leading to the generation of higher concentrations of NO2, which autocatalyzes the remaining ADN decomposition.