PtRu nanoparticles supported on ozone-treated mesoporous carbon thin film as highly active anode materials for direct methanol fuel cells

Ordered mesoporous thin-film carbon (TFC) material, of short channels vertical to the film, was synthesized by hard templating and deposited with PtRu nanocatalyst as an anodic material in a direct methanol fuel cell (DMFC). A series of PtRu bimetallic nanoparticles supported on ozone-pretreated carbon were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure (EXAFS) analysis. For 20 wt % PtRu catalyst supported on a 30 min ozone-pretreated TFC gave an unprecedented current density of 410 mA/mg _PtRu at 0.5 V relative to reference hydrogen electrode (RHE) at 60 °C. The ozone treatment method introduces an easily controllable way for surface modification of mesoporous carbon which was found to modulate the surface composition and structure of the deposited PtRu nanoparticles. The greatly enhanced methanol electrochemical oxidation activity, at an optimum ozone treatment, was ascribed to facile transport in the TFC structure, high dispersion of bimetallic nanoparticles, and an optimized surface Pt and Ru ensembles of 70:30 ratios for a bifunctional efficiency.