Production rates and destruction frequencies of ammonia in inductively coupled H2O/N2 and H2/N2 plasmas

Abstract We compared the production rates and the destruction frequencies of ammonia in inductively coupled H 2 O/N 2 and H 2 /N 2 plasmas. We observed that the production rates of ammonia ranged between 4 and 7 μmol/s both in the H 2 O/N 2 and H 2 /N 2 plasmas generated at rf powers between 100 and 160 W, corresponding to the energy cost of 23–25 mol/MJ. Almost the same production rates suggest the usefulness of H 2 O as the resource for hydrogenation of atomic nitrogen adsorbed on surfaces. On the other hand, the destruction frequency was 2–4 times higher in the H 2 O/N 2 than H 2 /N 2 plasmas. Although the H 2 O/N 2 plasma has a drawback in the destruction frequency, the present work shows its potential for the direct synthesis of ammonia from water with skipping the production of hydrogen.