NiCo/C-N/CNT composite catalysts for electro-catalytic oxidation of methanol and ethanol

Abstract

In this work, the catalyst precursor Ni3Co1/C-N was firstly fabricated by direct pyrolysis of NiCo salts/polyaniline (PANI) composite at 800°C under N2 atmosphere. Then the obtained Ni3Co1/C-N and multi walled carbon nanotubes (CNTs) particles were ground together to synthesize the Ni3Co1/C-N/CNT catalysts with different CNT mass percentages: Ni3Co1/C-N/CNT(15%), Ni3Co1/C-N/CNT(25%), Ni3Co1/C-N/CNT(35%), Ni3Co1/C-N/CNT(45%). The catalysts were characterized by SEM, TEM, XRD and XPS techniques. Cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were used to study the electrocatalytic activity of the prepared catalysts for oxidation of methanol and ethanol in alkaline media. Results show that among the prepared catalysts, the Ni3Co1/C-N/CNT(35%) presents the best catalytic activity for oxidation of both methanol and ethanol. The current density at 0.85V for oxidation of methanol and ethanol on the Ni3Co1/C-N/CNT(35%) reaches as high as 213mAcm−2 and 181mAcm−2, respectively, which has exceeded the results on the state of the art catalysts. For oxidation of both methanol and ethanol, the Ni3Co1/C-N/CNT(35%) catalyst also exhibits smaller electron transfer resistances, larger reaction rates and more stable electrocatalytic activity.