Electrocatalytic determination of free glycerol in biodiesel at nano nickel modified graphite electrode

Abstract

For the first time this study reported the success of using nanocrystalline hexagonal close-packed (hcp) nickel (Ni) modified composite graphite (CG) electrode (hcp-nano Ni/CG) for the electrocatalytic oxidation of glycerol in alkaline medium (0.1 M KOH). The hcp-nano Ni/CG electrode had an improve response and specificity on the electrocatalytic oxidation of glycerol over the bare CG. The electrocatalysis was the result of the formation of NiOOH during the oxidation process. The process was influenced by scan rate and concentration of glycerol. A linear relationship of concentration with current was obtained over concentration range of 0.5 – 12.0 mM glycerol with limit of detection (S/N = 3) at 0.033 mM glycerol. The hcp nano Ni modified CG electrode was applied for direct determination of free glycerol in biodiesel samples. As a glycerol sensor the hcp nano Ni modified CG is quite stable.