CARBON SUPPORTED NICKEL MANGANESE SPINEL OXIDE ELECTRODES: ARE THEY GOOD AT CATALYZING THE OXIDATION OF GLYCINE IN ALKALINE SOLUTIONS?

Protein is a kind of important organic matter and commonly found in organic wastewaters, such as domestic wastewater and food processing wastewater. As minimum units of protein, amino acids widely exist in wastewater and may cause carbon and nitrogen pollutions. Glycine is the simplest of amino acids, thus it serves as an important model compound in biophysics and biochemistry of proteins. Electrochemical oxidation of glycine, owing to the poor kinetics, is found to be efficient only in the presence of suitable electrocatalyst such as metallic nickel or carbon supported nickel oxide particles. Herein we have explored the possibilities of using a bimetallic catalyst based on nickel and manganese oxide towards enhancing the electrochemical oxidation activity of glycine. Three different composition of Nickel manganese oxide spinel material namely NiMn₂O₄, Ni_1.5Mn_1.5O₄ and MnNi₂O₄ was synthesized by a simple template-free hydrothermal route followed by a thermal treatment in air at 800°C. The structural properties of these materials were evaluated by XRD analysis and the catalysts morphology was characterized by SEM and EDS. The electrochemical properties was assessed by cyclic voltammetric studies which reveals that the as prepared spinel nickel manganese oxide materials displayed enhanced oxidation current density and lower anodic onset potential towards glycine oxidation in alkaline solution than the corresponding single oxides (NiO and Mn₂O₃).