and Cu/SiO2 delivered an ammonia production rate of 3.4 and 3.3 mmol.gcat -1 .h -1 with the N2 input flowrate of 6.2 sccm and power of 2 W, respectively (Fig. ). All these values are within range of each other despite the type of metal employed. When comparing with other researchers, who have reported to produce ammonia from water, the synthesis rate of 2.67 mmol gcat -1 h -1 from N2/water has been observed over the noble catalyst Ru/MgO at a N2 feed of 100 sccm and Vp-p of 8.23 kV. From our prepared catalysts, Co/SiO2, displays a comparative performance in terms of ammonia synthesis rate when employing N2 and sea water vapor at a N2 feed of 6.2 sccm and power of 2 W (about Vp-p of 4.12 kV) with a value of 3.7 mmol gcat -1 h -1 . An advantage, with respect to these reports is that a transition metal-based catalyst such as Co/SiO2 is lower in cost and there is a wider availability compared to noble metals such as Ru . However, for the N2 sea water vapor system is important to remember the challenging selectivity competition with N2O formation due to the oxygen presence related to the hydrogen source. This can explain the apparent no effect of the metal towards ammonia production.