Bimetallic catalysts provide the ability to tune catalytic activity, selectivity, and stability. Model catalysts with size-selected bimetallic clusters on well-defined supports offer a useful platform for studying catalytic mechanisms; however, producing size-selected bimetallic clusters can be challenging. In this study, we present a way to prepare bimetallic model (Pt_nB_m/alumina) cluster catalysts by depositing size-selected Pt₇ clusters on an alumina thin film, then selectively adding boron by exposure to diborane, and heating. The interactions between Pt₇/alumina and diborane were probed using temperature-programmed desorption/reaction (TPD/R), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering (ISS), plane wave density functional theory (PW-DFT), and molecular dynamic (MD) simulations. It was found that the diborane exposure/heating process does result in preferential binding of B in association with the Pt clusters. Borated Pt clusters are of interest because they are known to exhibit reduced affinity to carbon deposition in catalytic dehydrogenation. At high temperatures, theory, in agreement with experiment, shows that boron tends to migrate to sites beneath the Pt clusters, forming Pt–B–O_suf bonds that anchor the clusters to the alumina support.

中文翻译：

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乙硼烷与Pt ₇ /氧化铝的相互作用：尺寸控制的硼酸Pt模型催化剂的制备

双金属催化剂提供了调节催化活性，选择性和稳定性的能力。在明确定义的载体上具有尺寸选择的双金属簇的模型催化剂为研究催化机理提供了有用的平台。然而，生产尺寸选择的双金属团簇可能具有挑战性。在这项研究中，我们提出了一种通过在氧化铝薄膜上沉积尺寸选择的Pt ₇团簇，然后通过暴露于乙硼烷中并选择性地添加硼来制备双金属模型（Pt _n B _m /氧化铝）团簇催化剂的方法。Pt ₇之间的相互作用/氧化铝和乙硼烷使用程序升温解吸/反应（TPD / R），X射线光电子能谱（XPS），低能离子散射（ISS），平面波密度泛函理论（PW-DFT）和分子进行了探测动态（MD）模拟。发现乙硼烷的暴露/加热过程确实导致了B与Pt团簇的优先结合。硼酸的Pt簇是令人感兴趣的，因为已知它们在催化脱氢中对碳沉积表现出降低的亲和力。在高温下，理论与实验一致，表明硼倾向于迁移到Pt团簇下方的位置，形成Pt–B–O _suf键，将团簇锚定在氧化铝载体上。