Electrocatalysis of free glycerol at a nanonickel modified graphite electrode and its determination in biodiesel

This study reports the success of using an electrosynthesized nanocrystalline hexagonal close-packed (hcp) nickel (Ni) modified composite graphite (CG) electrode for the electrocatalytic oxidation of glycerol in alkaline medium (0.1 M KOH). The hcp-nano Ni modified CG had an improved response and remarkable 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 the scan rate and concentration of glycerol. A linear relationship between the concentrations of glycerol with the current was obtained over a range of 0.5–12.0 mM glycerol, with a limit of detection (S/N = 3) at 0.033 mM glycerol. The hcp-nano Ni modified CG electrode was applied to directly determine the free glycerol concentration in the biodiesel samples. As a glycerol sensor, the hcp-nano Ni modified CG is quite stable.

► Application of hcp nano Ni (electrochemically synthesized since the last one reported about 45 years ago) with average particle size ∼ 10 nm in electrocatalytic oxidation of glycerol. ► Fabrication of prototype glycerol sensor based on hcp nano Ni modified composite graphite. ► Analysis of free glycerol in biodiesel sample with amazingly low limit of detection (LOD) of 0.033 mM. ► To propose a cheap anode material, i.e. hcp nano Ni modified composite graphite for using in direct alcohol fuel cells (DAFCs).