Raman spectra of adsorbed ammonia on carbon-overlayered silver electrodes

Abstract

The laser-assisted carbonization of several organic amines and formate on silver electrode surfaces has been investigated. Carbon zones prepared in this way in all cases give rise to intense characteristic carbon features in the Raman spectra and in most cases are visible to the unaided eye. Raman spectroelectrochemical cells employed for the carbonization study permit draining, washing and refilling with a different electrolyte medium. After carbonization of the electrode surface using an oxidation–reduction cycle in aqueous formate, followed by careful washing, a fresh electrolyte medium of NH₃ in aqueous KF was added. A spectrum appeared which exhibited lines attributable to physically adsorbed NH₃ and to NH⁺₄, both in an environment of other ammonia/ammonium species from which water is apparently excluded.