Cerium-Promoted PtRu/MWNTs As the Anode Catalyst for Methanol Electro-Oxidation

In the present study, PtRuCe/MWNTs nanocatalysts synthesized via polyol process technique are applied as anode electro-catalyst in methanol electro-oxidation reaction (MOR). To characterize the nanocatalysts, TEM, XRD, EDS and XPS are investigated. Cyclic voltammetry and choronoamperometry are used to evaluate the electro-catalytic activity and stability of the catalysts in methanol electro-oxidation, respectively. Further addition of the Ce promoter to MWNTs-supported PtRu nanocatalyst shows the highest activity and the lowest onset potential in MOR at Ce to Pt molar ratio of 0.7. A significant enhancement of the forward anodic peak in cyclic voltammetry experiments is observed for the Ce-promoted PtRu catalyst with cerium to platinum molar ratio of 0.7, i.e. 349 mA/cm2.mgPt, in comparison with 182 mA/cm2.mgPt and 251 mA/cm2.mgPt, respectively, corresponding to Pt/MWNTs and PtRu(1:1)/MWNTs nanocatalysts. Furthermore, the chronoamperommetry results present a remarkable improvement in the final current density of PtRuCe/MWNTs (6.1 mA/cm2), compared to the un-promoted catalysts, having a decreasing propensity, i.e. PtRu/MWNTs (3.7 mA/cm2) and Pt/MWNTs (2.05 mA/cm2.mgcat). The improved performance of PtRuCe/MWNTs may be attributed to the formation of highly-dispersed Pt nanoparticles on the support, followed by a significant enhancement of bifunctional mechanism, as a result of cerium incorporation.