The Preparation and Catalytic Properties of Nanoporous Pt/CeO2 Composites with Nanorod Framework Structures
The Preparation and Catalytic Properties of Nanoporous Pt/CeO2 Composites with Nanorod Framework Structures
复制标题
纳米棒骨架结构纳米孔Pt/CeO2复合材料的制备及其催化性能
作者：
王海洋;段栋;马宸;时文宇;梁苗苗;王力群;宋晓平;高禄梅;孙占波
Pt/CeO 2催化剂具有纳米多孔结构，通过熔融纺丝Al 92 − XCe 8 PtX（X = 0.1; 0.3和0.5）带的简单脱合金化，然后煅烧来制备。采用X射线衍射（XRD）、场发射扫描电子显微镜（FESEM）和高分辨透射电子显微镜（HRTEM）对催化剂的物相组成和结构参数进行了表征。通过N2吸附-脱附测试表征了比表面积和孔径分布。通过三效催化剂（TWC）测量系统评价催化性能。结果表明，脱合金后的样品具有纳米棒的骨架结构。原位形成的Pt纳米颗粒被支撑并高度分散在CeO 2纳米棒表面上，并且具有2-5 nm范围内的尺寸。对于由熔纺Al91.7Ce8Pt0.3带制备的催化剂，50%CO转化温度（T50）为91 ℃，并且当温度升高至113 ℃时可以转化全部CO。X射线光电子能谱（XPS）测试表明，Pt 0. 3/CeO 2样品具有较丰富的氧空位; H2-TPR测试表明，Pt 0. 3/CeO 2样品对还原性气体具有较强的上级吸附能力，活性氧物种含量较高。实验结果表明，在反应气中存在水和CO2的情况下，催化剂的催化性能在130 h后仍保持不变。CeO 2/Pt纳米粒子的高比表面积、小孔径和Pt粒子尺寸以及CeO 2与Pt粒子之间的强相互作用是其良好催化活性的主要原因。Pt纳米颗粒嵌入CeO 2纳米棒的表面，抑制生长。因此，催化稳定性和耐水性优异。
Pt/CeO2 catalysts with nanoporous structures were prepared by the facile dealloying of melt-spun Al92−XCe8PtX (X = 0.1; 0.3 and 0.5) ribbons followed by calcination. The phase compositions and structural parameters of the catalysts were characterized by X-ray diffffraction (XRD), fifield emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The specifific surface area and pore size distribution were characterized by N2 adsorption–desorption tests. The catalytic properties were evaluated by a three-way catalyst (TWC) measurement system. The results revealed that the dealloyed samples exhibited a nanorod framework structure. The Pt nanoparticles that formed in situ were supported and highly dispersed on the CeO2 nanorod surface and had sizes in the range of 2–5 nm. For the catalyst prepared from the melt-spun Al91.7Ce8Pt0.3 ribbons, the 50% CO conversion temperature (T50) was 91 ◦C, and total CO could be converted when the temperature was increased to 113 ◦C. An X-ray photoelectron spectroscopy (XPS) test showed that the Pt0.3/CeO2 sample had a slightly richer oxygen vacancy; and a H2 temperature-programmed reduction (H2-TPR) test demonstrated its superior adsorption ability for reduction gas and high content of active oxygen species. The experiments indicated that the catalytic performance could be retained without any attenuation after 130 h when water and CO2 were present in the reaction gas. The favorable catalytic activities were attributed to the high specifific areas and small pore and Pt particle sizes as well as the strong interactions between the CeO2 and Pt nanoparticles. The Pt nanoparticles were embedded in the surface of the CeO2 nanorods, inhibiting growth. Therefore, the catalytic stability and water resistance were excellent.