Electrocatalytic oxidation of ammonia in the neutral medium using Cu2O.CuO film immobilized on glassy carbon surface

Abstract

Electrocatalytic ammonia oxidation reaction (AOR) was executed on the copper oxide layer, electrochemically deposited on a glassy carbon electrode (GCE) surface. The XPS analysis revealed that the oxide film contains 80% Cu(I) and 20% Cu(II) species. The EIS analysis suggests that the resultant surface can catalyze ammonia oxidation reactions efficiently. The as prepared GCE-Cu2O.CuO favored the neutral medium for executing AOR with a degradation rate of 3.76 × 10−4 mol min−1 cm−2. Kinetic investigation shows that ammonia oxidation involves a three electron transfer first-order reaction. Tafel analysis of current–potential polarization curves indicates that species such as NH3 or NHads and NH2ads intermediates do not influence the reaction rate, which made the electrode unique for carrying out AOR. The formal potential value of AOR was evaluated to be ~0.7 V vs Ag/AgCl (sat.KCl) having standard rate constant (k°) of 5.52 × 10−6 cm/s.