Catalytic Decomposition of Hydrazine over Supported Molybdenum Nitride Catalysts in a Monopropellant Thruster

The catalytic decomposition of hydrazine over a series of MoN_x/-Al₂O₃ catalysts with different Mo loadings was investigated in a monopropellant thruster (10 N). When the Mo loading is equal to or higher than the monolayer coverage of MoO₃ on -Al₂O₃, the catalytic performance of the supported molybdenum nitride catalyst is close to that of the conventionally used Ir/-Al₂O₃ catalyst. The MoN_x/-Al₂O₃ catalyst with a loading of about 23 wt% Mo (1.5 monolayers) shows the highest activity for hydrazine decomposition. There is an activation process for the MoN_x/-Al₂O₃ catalysts at the early stage of hydrazine decomposition, which is probably due to the reduction of the oxide layer formed in the passivation procedure.