LixCo3-xO4 solid solution nanocrystals supported on carbon black as a superior electrocatalyst for oxygen reduction reaction

We have synthesized LTxCo3-xO4 (x=0.05) solid solution nanocrystals through direct nucleation and growth of the lithium-cobalt oxide on a modified carbon black. The carbon-supported LixCo3-xO4 spinet nanocrystals with average particle size of approximately 4 nm, covered evenly on the surfaces of carbon in this hybrid. The electronic states of the LTxCo3-xO4/C were characterized by cyclic voltammogram (CV) and X-ray photoelectron spectroscopy (XPS) measurements. The electrocatalysis experiments in an alkaline solution showed that the oxygen reduction half-wave potential of LixCo3-xO4/C exhibited 67 mV more positive than that of Co3O4/C reference, revealing higher activity for oxygen reduction reaction (ORR). The remarkably improved activity resulted horn the strengthened chemical adsorption of surface-adsorbed oxygen and weakened adsorption of OH- groups at the solid solution surfaces. This information was important to understand the physical origin of the electro-catalytic activity of lithium-cobalt oxide catalysts during the ORR. (C) 2014 Elsevier B.V. All rights reserved.