Noticeably, for the N2/H2 reaction mixture the presence of the Co/SiO2 catalyst promoted the ammonia synthesis rate (𝑟 𝑁𝐻 3 ) to 6.3 mmol.gcat -1 .h -1 , which is threefold to that produced over the SiO2 support at similar experimental conditions (Fig. ). In general, the N2/H2 reaction mixture observed a greater impact from the metal content compared to the case when the sea water vapor is employed as hydrogen source. Besides, the metallic active centers possessing better activity than oxides like silica, with the possibility to delivered better ammonia production rate , since the selectivity competition with N2O does not exist in this case.