Ce0.8Sn0.2O2−δ–C composite as a co-catalytic support for Pt catalysts toward methanol electrooxidation

Abstract

Ce0.8Sn0.2O2−δ solid solution is fabricated using a simple one-step solvothermal method. The synthesized solid solution mixed with Vulcan XC-72 carbon black (denoted by Ce0.8Sn0.2O2−δ–C) is employed as a co-catalytic support for Pt catalysts toward methanol electrooxidation. X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 adsorption/desorption and temperature programmed reduction (TPR) are used to characterize the properties of Ce0.8Sn0.2O2−δ solid solution. The results show that Ce0.8Sn0.2O2−δ possesses a high specific surface area, an enhanced conductivity and a high oxygen storage capacity (OSC). Pt catalysts grown around Ce0.8Sn0.2O2−δ on carbon black form a special Pt–Ce0.8Sn0.2O2−δ–C triple junction structure, and their electrocatalytic properties are investigated in detail by a series of electrochemical methods. As compared with Pt/CeO2–C and commercial Pt/C catalysts, Pt/Ce0.8Sn0.2O2−δ–C catalyst exhibits superior electrocatalytic activity and long-term stability for methanol electrooxidation in acid media. The origin of the enhanced electroctatlytic properties for Pt/Ce0.8Sn0.2O2−δ–C is closely related to the OSC of Ce0.8Sn0.2O2−δ and the triple junction structure.