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

Abstract

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