Copper chromite is employed as a catalyst is certain rocket propellants. It is typically added in 1 to 5% quantities to whistle or composite rocket fuels which increases the burn rate. A range of other catalysts exist which can often be substituted for copper chromite. Examples are Iron oxide (red) and Manganese dioxide.
Copper chromite is very hard to make or obtain other than from dedicated pyro chemicals suppliers.
Copper chromite is poisonous and should be handled wearing a dust mask