Dioxygen fixation by a cobalt(II)–ammoniacal complex and its electroreduction in a nafion coated solid-state three-electrode cell

Abstract

The reduction potential for the Co^II–NH₃–O₂ system at a glassy-carbon electrode in a solid-state Nafion-coated cell is about 800 mV more positive than obtained for a glassy-carbon–Nafion film electrode when immersed in an aqueous solution containing Co^II, ammonia, and dioxygen (+0.3 and –0.5 V vs. Ag/AgCl, respectively); this is attributed to two different electrode reactions: reduction of [(NH₃)₅Co–O₂–Co(NH₃)₅]⁴⁺ in the absence of a contacting liquid electrolyte solution and free O₂ in aqueous Co^II–ammoniacal solution.