Straight hydrogen peroxide has been used as a monopropellant in atmosphere quite a bit - most famously in the Thiokol jump belt. The catalytic grid is silver.
The holy grail of propellants would run at ambient temperature (no heat signature), contain no metals (no radar signature), burn invisibly (no light signature at night or smoke trail in the day) and inaudibly (good luck with that one), and have no detectable odor or health effects. When I was in the rocket science racket we acknowledged all these academic points and moved on to maximizing specific impulse.
