Thermal behaviour of Cu and Au nanoparticles grown on CeO2 thin films
Thermal behaviour of Cu and Au nanoparticles grown on CeO2 thin films
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DOI：
10.1016/j.apsusc.2021.151656
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发表时间：
2021-10
影响因子：
6.7
通讯作者：
R. Megginson;F. Grillo;S. Francis;V. Z. C. Paes;H. Trombini;P. L. Grande;A. Rossall;J. van den Berg;C.J. Baddeley conceptualisation
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文献类型：
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作者：
R. Megginson;F. Grillo;S. Francis;V. Z. C. Paes;H. Trombini;P. L. Grande;A. Rossall;J. van den Berg;C.J. Baddeley conceptualisation
双金属催化剂通常比它们的单金属催化剂更具活性和/或选择性。这类催化剂的行为往往强烈地依赖于这两种元素的摩尔比以及纳米颗粒的大小和与载体材料的相互作用。X射线光电子能谱(XPS)是研究催化体系电子性质的一种很好的表面分析技术。当存在纯粒子和合金粒子的混合物时，由于XPS是一种空间平均技术，从XPS中提取信息更加困难。最近，中能离子散射(MEIS)技术被用来研究平面上纳米粒子的深度相关组成。在这里，我们结合这两种技术来研究沉积在Si(1：1：1)上的超薄CeO2薄膜上的铜和金纳米颗粒的性质，并考察了在超高真空环境中保持并暴露在空气中的样品的形貌和化学组成随退火温度的变化。选择了Cu/Au/CeO2/Si(1：1：1)作为模型体系，研究了CuAu/CeO2催化剂的催化性能如何依赖于离散的铜和Au粒子的存在，以及完全混合的CuAu/Au体系。
Bimetallic catalysts are often more active and/or selective than their monometallic counterparts. The behaviour of such catalysts is frequently strongly dependent on the molar ratio of the two elements as well as nanoparticle size and the interaction with the support material. X-ray photoelectron spectroscopy (XPS) is an excellent surface analytical technique for probing the electronic properties of catalytic systems. When a mixture of pure and alloyed particles is present, it is more difficult to extract information from XPS given that it is a spatial averaging technique. Recently, the technique of medium energy ion scattering (MEIS) has been exploited to investigate the depth-dependent composition of nanoparticles on planar surfaces. Herein, we combine the two techniques to investigate the nature of Cu and Au nanoparticles deposited onto ultrathin CeO2films on Si(1 1 1) examining their morphology and chemical composition as a function of annealing temperature for samples that have been maintained in an ultrahigh vacuum environment and exposed to air. The Cu/Au/CeO2/Si(1 1 1) is chosen as a model system in order to provide insight into how the catalytic properties of Cu/Au/CeO2depend on the presence of discrete Cu and Au particles versus fully intermixed Cu/Au systems.