Highly active and stable PtRuSn/C catalyst for electrooxidations of ethylene glycol and glycerol

Abstract

Electrocatalytic oxidations of ethylene glycol and glycerol were studied over a carbon-supported PtRuSn catalyst (PtRuSn/C), which was prepared with a Pt:Ru:Sn atomic ratio of 5:4:1 using a colloidal method combined with a freeze-drying procedure at room temperature. The ternary PtRuSn/C catalyst was characterized by various physicochemical analyses such as X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and X-ray absorption-near-edge spectroscopy (XANES). The ternary PtRuSn catalyst showed noticeable modifications on the catalyst phases from Pt or PtRu in regards to structural and electronic features, such as a change in lattice parameter and electronic modification in unfilled d band states of Pt atoms. The structurally and electronically modified PtRuSn/C catalysts substantially enhanced the electrocatalytic activities for ethylene glycol and glycerol oxidations, resulting in larger peak currents and lower onset potentials of the electrooxidations. By incorporating the Ru and Sn elements onto the ternary PtRuSn/C catalyst, efficient oxidative removals of CO or CO-like carbonaceous intermediate species produced during the reaction were also possible, thus preventing poisoning of the active Pt sites. Consequently, significant enhancements of electrocatalytic activity and stability over the ternary PtRuSn/C catalyst could be achieved for the electrooxidations of ethylene glycol and glycerol.