However, the presence of seawater alters such mechanisms by adding the excitation and/or ionization of water molecules. In our case, the nitrogen plasma can react with H2O vapor molecules to generate NH and OH radicals where the extraction of H from water molecules plays an important role in the formation of ammonia. This deduction is in good agreement with other researchers . In this work H2O vapor molecules could cause the quenching of N2 vibrational levels given the N2/H2O vibrational-translational relaxation, reducing electron density. This added to the consumption of nitrogen excited species to form N2O reduces the overall ammonia synthesis rate . OH* could also be generated from the dissociation of H2O molecules. Nevertheless, the presence of such OH* species would lead to the formation of H2O2, which was not detected in this work. Therefore, such hydroxyl radicals with significant short life could get dissociated to H* and O* subsequently. Experimental results in this work indicated that even if the Co/SiO2 catalyst displayed good ammonia synthesis rate, a strongest N2O-related spectra was detected, indicating the strong competition imposed by N2O formation. While the Ag/SiO2 catalyst displayed no OES spectra related to NOx species it showed a competitive activity relative to the Co/SiO2, as discussed previously. Meaning the surface interactions might be overcoming the gas events. This also shows the importance of the silica substrate that as mentioned above can aid in the N2O decomposition. Hence, work can focus on enhancement of the catalytic activity of oxygen-phobic metals or electron density on the catalyst surface to dissociate N2 and maintain relatively weak intermediate bindings effectively. Such active metals would be ideal if they possess high affinity to oxidative oxygen species to offer strong bindings or act as oxygen sinks to hinder the formation of nitrogen oxide.