Effects of Solvent and Concentration of Borohydride for the Preparation of PtRu/C Electrocatalysts for Direct Methanol Fuel Cell Anodes - A Factorial Design Study

A factorial design study was performed to evaluate the influence of the BH4-:PtRu molar ratio (5 and 15) and the solvent (water or isopropyl alcohol) in the preparation of PtRu/C electrocatalysts for Direct Methanol Fuel Cell (DMFC) anodes. The obtained materials were characterized by Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). For both solvents increasing the BH4-:PtRu molar ratio from 5 to 15 leads to a decrease of the mean nanoparticle sizes and, using water as solvent, it was observed better distributions of the nanoparticles on the carbon support than using isopropyl alcohol. The DMFC maximum power density was obtained using a electrocatalyst prepared with a BH4-:PtRu molar ratio of 15 and water as solvent. The analysis of the effect of interaction of the two parameters showed that the variations of the maximum power density was more dependent of the BH4-:PtRu molar ratio than of the solvent used.