Study of the oxidation of ammonia in contact with silver dispersed on zeolite and the formation of cyclotriazane confined in the porosity

While the molecule Cyclotriazane (c-N3H3) has been estimated to be stable at room temperature, it has not been isolated yet. The synthesis and stabilization of cyclotriazane has been reported to occur in a zeolite. In 1977, Karl Seff and his colleagues claimed the identification of c-N3H3 by reacting ammonia (NH3) over a silver-exchanged LTA zeolite. The authors proposed c-N3H3to be stabilized by Ag+ in alpha cage of the zeolite. Yet, this result has not be reproduced since and as a matter of fact the synthesis of cyclotriazane by oxidative cyclisation of NH3 is in question. We studied the reactivity of NH3 on a silver-doped LTA zeolite by operando Diffuse Reflectance Infrared FT (DRIFT) spectroscopy. We observed a signal that that cannot be assigned to a known compound yet. The knowledge of the oxidation state of framework silver shall provide indirect evidence whether or not the oxidation of ammonia may occur and thus the possible formation of N-N bonds.