We observed that ammonia could be produced effectively from sea water vapor and N2 over the SiO2 catalyst at the relatively low N2 feed flowrate of 3.1 sccm, as shown in Fig. . At this N2 flowrate and an input plasma power of 2 W, 1.8 mmol.gcat -1 .h -1 of ammonia was produced from N2/sea water vapor system while the highest ammonia synthesis rate could be obtained at the feed flowrate of 6.2 sccm with a value of 2.8 mmol.gcat -1 .h -1 . Noticeably, at similar conditions, an ammonia synthesis rate of 2.6 mmol.gcat -1 .h -1 was obtained from the N2/H2 system with the N2 flowrate of 3.1 sccm corresponding to the N2:H2 ratio of approximately 4.0 (H2 was fixed at 12.5 sccm), as shown in Fig. ). The increase in the plasma power above 2 W, such as 3W, 5W, and 6 W, led to an enhancement in the ammonia synthesis rate when using N2/H2 mixture relative to N2/sea water vapor (Fig.