Catalytic Decomposition of Hydroxylammonium Nitrate Monopropellant discusses preparation and testing of HAN-water blends and the use of Iridium as catalyst.
Is Hydroxylammonium nitrate propellant "green" enough to ever be used in a cubesat? In this context, "green" refers to its lower toxicity when compared with hydrazine.
The question is not so much compatibility with the cubesat itself as it is with the safety requirements of the most common space deployment options and cubesat guidelines related to stored chemical energy.
According to Wikipedia NH3OHNO3 is a fuel/oxidizer blend, also known as AF-M315E. It would likely be used in a spacecraft as an aqueous solution liquid propellant (the solid salt has stability issues), and may be more efficient (per volume) than Hydrazine.
According to GPIM (Green Propellant Infusion Mission) / STP-2
Delivering approximately 50% higher ρΙsp than hydrazine (5% higher Isp combined with a 46% higher density, AF-M315E offers comparable performance to traditional storable bipropellants for low V missions while employing roughly half the number of components, thereby retaining the well-established increased reliability and reduced cost of traditional monopropellants. Many design issues and failure modes associated with long-duration interplanetary missions (e.g. control of mixture ratio, of propellant vapor diffusion and reaction, oxidizer flow decay) do not apply to an equally capable AF-M315E system.