Investigation of Co3O4 nanorods supported Pd anode catalyst for methanol oxidation in alkaline solution

A Co3O4 nanorod supported Pd electro-catalyst for the methanol electro-oxidation(MEO) has been fabricated by the combination of hydrothermal synthesis and microwave-assisted polyol reduction processes. The crystallographic property and microstructure have been characterized using XRD, SEM and TEM. The results demonstrate that Pd nanoparticles(Pd NPs) with a narrow particle size distribution(3-5 nm) are uniformly deposited onto the surface of Co3O4 nanorods. Electrochemical measurements show that this catalyst having a larger electrochemically active surface area and a more negative onset-potential exhibits enhanced catalytic activity of 504 m A/mg Pd for MEO comparing with the Pd/C catalyst(448 m A/mg Pd). The dependency of log I against logv reveals that MEO on Pd-Co3O4 electrode is under a diffusion control.Electrochemical impedance spectroscopy(EIS) measurement agrees well with the CV results. The minimum charge transfer resistance of MEO on Pd-Co3O4 is observed at-0.05 V, which coincides with the potential of MEO peak.