Evidence by SERS of azide anion participation in ammonia electrooxidation in alkaline medium on nanostructured Pt electrodes

Evidence of the participation of adsorbed azide anion (N3-) in the electrooxidation of ammonia in alkaline medium on nanostructured Pt electrodes has been found by using surface-enhanced Raman spectroscopy. This finding is discussed in terms of the Gerischer–Mauerer’s mechanism for ammonia oxidation. The formation of azide anion would take place through the recombination of NH3 and N2H4,ad (and maybe other N2Hx (x = 2–4) species). The results support the Gerischer–Mauerer’s mechanism in which partially dehydrogenated ammonia adsorbates are believed to play a role as active intermediates in the selective oxidation of ammonia.