Methanol Electro-Oxidation in Alkaline Medium by Ni Based Binary and Ternary Catalysts: Effect of Iron (Fe) on the Catalyst Performance

Resumo

Pt free methanol electro oxidation catalysts with stable response are of interest to reduce the overall cost of the direct methanol fuel cell (DMFC). Here, nickel based bi and tri metallic catalysts have been prepared on multiwall carbon nanotube (MWCNT) support by incipient wetness impregnation method. Methanol oxidation performance was investigated in 1 M KOH by cyclic-voltammetry (CV) and chronoamperometry (CA). The results of electrochemical tests showed that among all the catalysts tested, catalyst sample, CAT-3 exhibited the highest current density of 125.5 mA/cm² and have stable electrochemical response, which is very promising. These catalysts have been characterized by field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray-(EDX), transmission electron microscopy (TEM), X-ray diffraction XRD and X-ray photoelectron spectroscopy (XPS) to study the structural and morphological properties. Characterization results revealed small and uniform particle size distribution and better homogeneity in CAT-3. It was also observed that addition of ‘Fe’ in tri metallic catalyst lowers the Cu contents in the catalysts and in the contrary lowers the electro-catalytic performance. All the catalyst found to be quite stable and CAT-3 gave the highest oxidative current response, which is attributed to higher Cu contents.