Manganese carbonate as an efficient electrocatalyst for the conversion of ammonia (NH4+/NH3) to dinitrogen

Abstract

Energy generation from a sustainable renewable source is seen as an imperative tool to meet the energy demand of the present day. Moreover, obtaining clean energy fuel e.g., H₂ is the need of the hour and hence, oxidation of ammonia might be a solution to this milestone. Mn₂(CO₃)₃ deposited electrochemically on the surface of a Pd electrode is a good electrocatalyst for the oxidation of ammonia (AOR) to dinitrogen. The AOR occurs in solutions containing Na₂CO₃ and NH₄OH as electrolytes. The Mn₂(CO₃)₃/Pd electrode in 0.5 M NH₄OH & 1.0 M Na₂CO₃ has a high electrocatalytic oxidation current density of 6.4 mA cm⁻² at anodic potential of 1.16 V vs. NHE. Chronoamperometric experiments, for the durability test, point out that Mn₂(CO₃)₃ is stable for over 4 h towards the ammonia oxidation reaction. Also, on careful investigation of the products formed upon oxidation of ammonia, only nitrogen as a product was observed.