Examination of the electroactive composites containing cobalt nanoclusters and nitrogen-doped nanostructured carbon as electrocatalysts for oxygen reduction reaction

A series of electroactive composites containing cobalt nanoclusters and N-doped graphite-like carbon is obtained by catalytic chemical vapour deposition (CCVD) using Mg-Co-Al layered double hydroxides and acetonitrile. The influence of synthesis temperature, e.g. 600, 700 and 800 degrees C on their physico-chemical properties is examined by means of X-ray diffraction, elemental analysis, thermal analysis, nitrogen sorption, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy. N-doped graphite-like carbon in the catalysts shows various morphologies. The composite prepared at 600 degrees C contains plate-like particles, whereas those synthesized at 700 and 800 degrees C, contain not only plate-like particles but also multi-walled carbon nanotubes. The concentration of nitrogen uniformly incorporated in the carbon framework is ca. 2 wt %. The electrocatalytic properties of the catalysts for oxygen reduction reaction (ORR) are evaluated in alkaline media by cyclic voltammetry and rotating disk electrode (RDE) measurement. The composites are proved to have the ability to reduce oxygen according to 2-electron pathway. (C) 2012 Elsevier B.V. All rights reserved.