Ordered mesoporous carbons (OMCs) as supports of electrocatalysts for direct methanol fuel cells (DMFCs): Effect of the pore characteristics of OMCs on DMFCs

Two types of ordered mesoporous carbons (OMCs-FT and OMCs-F) with different hexagonal pore frameworks were synthesized via two soft template routes. Structural characterizations revealed that OMCs-FT possessed broader mesopore range, more enhanced mesoporosity and higher surface area, compared with the counterpart of OMCs-F. In order to systematically investigate the relationship between the pore characteristics and electrochemical performances, two catalysts of OMCs-FT/Pt and OMCs-F/Pt were achieved by ethylene glycol-assisted reduction procedure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements indicated that face-centered cubic Pt nanoparticles with an average size of 5.3 nm were homogeneously deposited on OMCs-FT while the mean size of 5.5 nm Pt nanoparticles had a relatively ransom dispersion on OMCs-F supports with some aggregations. The electrochemical results disclosed that OMCs-FT/Pt catalyst exhibited higher electrocatalytic activity and better stability than OMCs-F/Pt and commercially available E-TEK/Pt catalysts for methanol electro-oxidation. The broad mesopore range, enhanced mesoporosity and high surface area of OMCs-FT supports were considered to be the main reasons for its enhanced catalytic activity. (C) 2009 Published by Elsevier B.V.