ZnO表面与PdZn纳米结构之间接触的协同作用：选择性1,3-丁二烯加氢的金属间位点的形貌和化学性质影响,ACS Catalysis

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ZnO表面与PdZn纳米结构之间接触的协同作用：选择性1,3-丁二烯加氢的金属间位点的形貌和化学性质影响
ACS Catalysis ( IF 11.3 ) Pub Date : 2016-12-22 00:00:00 , DOI: 10.1021/acscatal.6b03009
Eva Castillejos-López ₁ , Giovanni Agostini ₂ , Marco Di Michel ₂ , Ana Iglesias-Juez ₃ , Belén Bachiller-Baeza ₃

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在这项工作中，采用了不同形状的ZnO载体来研究其对PdZn纳米结构的影响。我们的目标是了解ZnO形态的作用，以及主要的暴露面（极性（0001），非极性（112̅0）或非极性（101̅0）面）对所形成的PdZn合金的结构和电子性能及其对其影响的作用。 1,3-丁二烯选择性加氢的化学性质。已经完成了包括原位同步加速器X射线衍射（XRD）和原位X射线吸收光谱（XAS）测量以及原位漫反射红外傅里叶变换光谱（DRIFTS）和质谱（MS）的多技术方法，以实现了解PdZn合金的形成以及结构和电子性能。通过高分辨率透射电子显微镜（HRTEM），吸附CO的傅里叶变换红外光谱分析（CO-FTIR）和X射线光电子能谱（XPS）获得了互补的表征。合金化程度和PdZn纳米颗粒的形状取决于接触的ZnO表面。合金中Zn的百分比从非极性（101̅0）增大到非极性（112̅0）和极性（0001）面。此外，锌修饰了Pd纳米颗粒上低配位的表面位点，增加了Pd电子密度，并延长了在二烯烃加氢中起关键作用的晶格键的伸长，但重要的是，结果揭示了其对合金相结构的敏感性。反应。看来PdZn（100）表面构成了1的部分加氢的活性和选择性催化相 3-丁二烯。同步DRIFTS使我们能够分析1,3-丁二烯加氢过程中表面物质的相对浓度，并证实了吸附的中间烯烃的不同稳定性取决于纳米粒子的形状和合金化程度。基于所形成的合金的结构和电子性质，已经解释了1，3-丁二烯氢化反应中选择性的差异。

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Synergy of Contact between ZnO Surface Planes and PdZn Nanostructures: Morphology and Chemical Property Effects in the Intermetallic Sites for Selective 1,3-Butadiene Hydrogenation

In this work, differently shaped ZnO supports were employed to study their effect on PdZn nanostructures. Our goal was to understand the role of ZnO morphology and consequently the major exposed faces (polar (0001), nonpolar (112̅0), or nonpolar (101̅0) facets) on the structural and electronic properties of the formed PdZn alloys and how it affects their chemical properties in selective 1,3-butadiene hydrogenation. A multitechnique approach that included in situ synchrotron X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS) measurements combined with in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) and mass spectrometry (MS) has been accomplished to understand the formation of the PdZn alloy and the structural and electronic properties. Complementary characterization was obtained by high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy analysis of adsorbed CO (CO-FTIR), and X-ray photoelectron spectroscopy (XPS). The alloying degree and the PdZn nanoparticle shape depend on the contacted ZnO surface. The percentage of Zn in the alloy increases from nonpolar (101̅0) to nonpolar (112̅0) and to polar (0001) facets. Moreover, zinc modifies low-coordinated surface sites on Pd nanoparticles, increases Pd electron density, and produces elongation of the lattice bonds which play a crucial role in diolefin hydrogenation, but also importantly, the results unravel the sensitivity to the alloy phase structure of this reaction. It seems the PdZn(100) surface constitutes an active and selective catalytic phase for partial hydrogenation of 1,3-butadiene. Synchronous DRIFTS has allowed us to analyze the relative concentrations of surface species during 1,3-butadiene hydrogenation and confirmed the different stabilities of the adsorbed intermediate alkenes depending on the nanoparticle shape and degree of alloying. The differences in selectivities in the 1,3-butadiene hydrogenation reaction have been explained on the basis of of the structural and electronic properties of the formed alloy.

更新日期：2016-12-22

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