Effect of Dispersion on Catalytic Performance of Supported Pt Catalysts for CO Oxidation

A series of ceria, silica, and γ-alumina-supported platinum catalysts were prepared by the incipient-wetness impregnation method. Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to determine the dispersion of Pt. For the Pt/CeO2 catalysts, XRD studies suggest that Pt was better dispersed as its concentration decreased. This observation correlated well with XPS analysis. For catalysts with the same Pt mass loading, TEM and XRD results suggest that Pt dispersion displays an increasing order as Pt/SiO2 < Pt/γ-Al2O3 < Pt/CeO2. Catalytic activities for CO oxidation were investigated. Results showed that the 0.25 wt% Pt/CeO2 exhibited a higher activity than other oxide supported catalysts with a turnover frequency of 2.2 × 10−3 CO2 per total Pt per second at room temperature.

摘要以氧化铈、氧化硅和氧化铝为载体, 采用浸渍法制备了一系列不同负载量的 Pt 基催化剂, 并利用透射电子显微镜、X 射线粉末衍射和 X 射线光电子能谱等技术对催化剂进行了表征. 结果表明, 对于 Pt/CeO2 催化剂, 随着负载量减小, Pt 的分散度提高; 对于相同负载量的 Pt 基催化剂, 各催化剂上 Pt 分散情况为: Pt/SiO2 < Pt/γ-Al2O3 < Pt/CeO2. CO 氧化反应结果表明, 0.25% Pt/CeO2 催化剂表现出更加优良的低温活性, 室温下其单位 Pt 原子上 CO2 的生成速率为 2.2 × 10−3 s−1.

Highly dispersed Pt species, including single atom and two-dimensional clusters, are active for CO oxidation at room temperature.Figure optionsDownload as PowerPoint slide