Synthesis of Oxide Based Ceramic Thin Films for Methanol Electro-Oxidation in Direct Methanol Fuel Cells

Abstract

Methanol electrochemical oxidation in direct methanol fuel cell (DMFC) is considered as an efficient pathway for generating renewable energy with low pollutant emissions. In this work, NiO, CuO, Cr2O3, NiO-CuO and Ni1-x Crx O2 thin films were synthesized by a simple dip-coating method and tested for electro-oxidation of methanol. These synthesized electrocatalysts were characterized by X-ray diffraction spectroscopy (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. The electro-catalytic activity for methanol oxidation was studied by different techniques such as linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). In the presence of 0.3 M methanol, the current densities of NiO-CuO and Ni1-x Crx O2 thin films are 6.1 mA0.5cm-2 and 6.5 mAcm-2 vs. 0.6 V. The increase in the catalytic activity of NiO-CuO and Ni1-x Crx O2 thin films can be due to a synergistic effect between metal oxides. The findings of EIS and CA also support the above results and help to explain the assumptions described. All the results of NiO-CuO and Ni1-x Crx O2 thin films showed better electrocatalytic activity, lower charge transfer resistance, good stability, and resistant to poisoning effect as compare to pure NiO, CuO, and Cr2O3 thin films. These catalysts are less expensive and can be a good candidate for the direct methanol fuel cell.