Key issues in the preparation of DMFC electrocatalysts

In this work, incipient wetness (IW) method was explored as the preferred method for the preparation of Pt-Ru/C catalysts. Pt-Ru dual active site, in which Pt and Ru are in neighboring sites, is needed for the anodic oxidation of methanol to carbon dioxide, electron and proton in direct methanol fuel cell (DMFC). Catalyst with 30% metal loading and Pt:Ru ratio of 1 gives the best performance in the anodic oxidation of methanol. Optimization of catalyst activation procedure was also performed in which H2 concentration ⩽10% in the reducing gas was preferred to avoid agglomeration of the active metals. Extended X-ray absorption fine structure (EXAFS) used to quantify the amount of Pt-Ru dual active sites revealed that IW method is indeed the method of choice for the preparation of Pt-Ru/C catalyst with more Pt-Ru active sites and higher catalytic activity. Carbon nanotube-vapor grown carbon fiber (CNT-VGCF) was prepared for use as the support for the preparation of supported Pt-Ru catalyst. Pt-Ru/CNT-VGCF was found to be more active than Pt-Ru/ XC-72 with the same metal loading using the same preparation method.