Figure 4.

NH₄⁺ formation from N₂ in the presence of Ni, Fe metals and alloys at 200°C. The dashed lines correspond to the Ar blank. The concentrations of KCl in the experiments were 459 μmol.kg^-1 in A, B and 476 μmol.kg^-1 in C, D. Results are normalized to 1 m² of surface area.