Effect of pore geometry on the electrocatalytic performance of nickel cobaltite/ carbon xerogel nanocomposite for methanol oxidation

Abstract

A new nickel cobaltite/carbon xerogel nanocomposite (NiCo2O4/CX) is obtained by preparing carbon xerogel (CX) by using sol-gel technique followed by growing the NiCo2O4 nanoneedles over CX using hydrothermal method. The used characterization techniques are XRD, HRTEM, FESEM and surface area measurements. The physicochemical properties of NiCo2O4/CX show face centered cubic nanoneedles -like structures containing different lengths and widths. In addition, BET analysis clarify that NiCo2O4/CX nanocomposite is mesoporous with uniform cylindrical pore geometry with two modular systems compared to narrow necks ink-bottle pore geometry for pristine NiCo2O4. Electrocatalytic activity and stability of glassy carbon modified electrode with NiCo2O4/CX towards methanol electro-oxidation in basic medium are studied using cyclic voltammetry and chronoamperometry techniques. Data shows, the NiCo2O4/CX modified electrode gives a catalytic current density of 98 mA cm−2 at 0.29 V with a good stability of 90.6% current retention after 100 repetitive cycles compared to 37.8 mA cm−2 at 0.38 V for pristine NiCo2O4. The highly electrocatalytic activity of NiCo2O4/CX modified electrode is correlated to the synergistic effects between the pore geometry and accessible porosity.