Preparation Of Rare Earth Doped PtRu/C Catalysts And Their Properties For Methanol Electrooxidation

Commercial PtRu/C catalyst was doped with rare earth by chemical reduction and sintering treatment methods, resulting in a series of PtRuRE/C (RE = La, Eu, Gd, Y, Sm and Er) catalysts. The catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). And the reaction process of methanol electrocatalytic oxidation on the catalyst was investigated further by in situ Fourier Transform Infrared (FTIR) spectroscopy at a molecule level. The main results and conclusions are summarized as follows: (1) The preparation condition of rare earth doped PtRu/C catalysts was optimized. It was found that the optimum preparation conditions were the sintering temperature of 150℃and the atomic ratio of Pt:Ru:RE = 1:1:_0.3; (2) The rare earth doping did not change the average size of PtRu/C catalysts, whose surface was modified by both RE metal and oxide state, and the oxide was the main state. Cyclic voltammetry and chronoamperometry tests demonstrated that the electrocatalytic activity and stability of PtRuRE/C catalysts were higher than that of the JM PtRu/C for methanol oxidation (except for PtRuGd/C), yielding a decreasing order of PtRuEu/C > PtRuEr/C > PtRuY/C > PtRuSm/C > PtRuLa/C > JM PtRu/C > PtRuGd/C. It was indicated that the rare earth doping except for Gd effectively promoted the activity and stability of JM PtRu/C for methanol oxidation, and the PtRuEu/C exhibited the best performance; (3) Studies of in situ FTIR spectroscopy indicated that the adsorbates derived from methanol dissociative adsorption on the catalysts were the linear-bonded CO (COL). The rare earth doping increased the Stark tuning rates of catalysts, which gave a decreasing order of PtRuEu_0.3/C > PtRuEr_0.3/C > PtRuY_0.3/C > JM PtRu/C. It was indicated that the electronic effect of rare earth lowered the Pt-CO band energy to improve the activity of rare earth doped catalysts for methanol oxidation and the CO-tolerance performance, and the property of Eu doped catalyst was the highest, which was in good agreement with the electrochemical results. In situ time-resolved FTIRS results further confirmed that the Eu doping manifestly increased the reaction rate of JM PtRu/C catalyst for methanol oxidation...