Synthesis of hexagonal CoAl-layered double hydroxide nanoshales/carbon nanotubes composite for the non-enzymatic detection of hydrogen peroxide

Abstract

A nanocomposite comprising hexagonal CoAl-layered double hydroxide nanoshales with multiwall carbon nanotubes (MWCNTs) was synthesized by reflux heating. The nanocomposite was then applied to modify a carbon paste electrode. The modified electrode was then applied to fabricate a non-enzymatic hydrogen peroxide sensor. Hydrogen peroxide was electrocatalytically oxidized on the modified electrode surface, while its electroreduction was performed by an enhanced direct electron transfer to the electrode surface. The catalytic rate constants of the hydrogen peroxide electrooxidation were processed by an active cobalt species, and the diffusion coefficient of hydrogen peroxide was reported. An amperometric method was developed for determination of hydrogen peroxide based on its electrocatalytic oxidation with a sensitivity of 118.0mAdm3mol−1cm−2 and a limit of detection of 10μmoldm−3. In addition, amperometric method based on hydrogen peroxide electroreduction had a sensitivity of 42.0mAdm3mol−1cm−2 and a limit of detection of 40μmoldm−3. The sensor had the advantages of high activity and sensitivity, with a simple fabrication method without complications of immobilization steps and using any enzyme or reagent.