Evaluation of Graphite/AgCl Composite as a New and Highly Efficient Electrocatalyst for Electroxidation of Oxalic Acid

Graphite/AgCl composite is described as an efficient electrocatalyst for the electroxidation of oxalic acid (OA). Graphite/AgCl was synthesized by the precipitation of AgCl on graphite sheet via drop wise addition of Cl- into an Ag+ solution, containing dispersed graphite. The material obtained was characterized by scanning electron microscopy. The composite was mixed with mineral oil as binder and used as carbon paste electrode for electrocatalytic oxidation of OA. The composite electrode exhibited appropriate catalytic activity for the electrooxidation of OA, leading to a substantial increase in anodic peak current, in comparison with the unmodified carbon paste electrode. Electrochemical impedance spectroscopy showed a substantial decrease in charge transfer resistance of OA oxidation at graphite/AgCl composite electrode, compared to that graphite paste electrode. The electrode showed appropriate selectivity compared to some compounds like citric acid, lactic acid, ascorbic acid and tartaric acid. Cyclic voltammetry at different scan rates and also various pH conditions gave some evidences about the mechanism electrooxidation of OA at graphite/AgCl electrode