Characterization and oxygen reduction activities of boron-doped ordered mesoporous carbons synthesized by soft-template method

Abstract

Boron-doped ordered mesoporous carbons were synthesized by a one-pot soft-templating strategy, where resorcinol and formaldehyde were used as carbon sources, boric acid was used as a boron source and Pluronic F127 was used as structure directing agent. The effect of temperature and the boric acid content on the physical and electrochemical properties of the resultant materials were investigated. Inductively-coupled plasma atomic emission spectroscopy (ICP-OES) was used for elemental analysis of the samples. The synthesis temperature did not have an overall positive effect on the doped-boron percentage, however there was a clear increase in the boron-doping when both the temperature and the boric acid content were increased. Nitrogen adsorption analysis isotherms showed that the samples had similar ordered mesoporous structures with surface areas varying between 535 and 712 m2/g. The uniform morphology in transmission electron microscopy (TEM) also confirmed the ordered mesoporous structure. Cyclic voltammetry analysis indicated that the highest oxygen reduction activity (-0,28 mA/cm2) was achieved with the highest boron-doping percentage (0.29%) for a temperature of 77 °C and boric acid to carbon ratio of 2. These results show that the boron-doped ordered mesoporous carbon is a promising material as a catalyst support for improving the oxygen reduction activity.