The synergistic effects of driving frequency of the discharge and catalysis of iron and molybdenum wires when they are placed in nitrogen-hydrogen radio-frequency and microwave plasmas were investigated. The ammonia yield increased in the plasmas prepared using both driving frequencies, but the hydrazine yield increased only in the radio-freguency discharge with the catalysts. The direct adsorption of NHx formed in the plasma on the catalyst surface followed by the formation of NH3 and N2H4 are considered as a reaction scheme in the radio-frequency discharge. On the other hand, the adsorption of N atoms and/or formation of the metal-N bond favors the formation of ammonia but does not affect the hydrazine formation in the microwave discharge.