Fig. 5. Summary of species evolution during the catalytic cycle, species shaded in green observed in the ME drifts experiments. [Cu²⁺(OH^–)]⁺ is consumed to make Cu–N( O)–NH₂, followed by bidentate nitrate and finally a Cu complex with both NO type and NH₃ ligands (as anticipated in the mechanism proposed by Janssens et al.10).