Oenema Jogchum, Hofmann Jan P, Hensen Emiel J M, Zečević Jovana, de Jong Krijn P
Inorganic Chemistry and Catalysis Debye Institute for Nanomaterials Science Utrecht University Universiteitsweg 99 Utrecht 3584 CG The Netherlands.
Laboratory for Inorganic Materials and Catalysis Department of Chemical Engineering and Chemistry Eindhoven University of Technology P.O. Box 513 Eindhoven 5600 MB The Netherlands.
ChemCatChem. 2020 Jan 18;12(2):615-622. doi: 10.1002/cctc.201901617. Epub 2019 Oct 30.
The location of Pt nanoparticles was studied in Pt/zeolite Y/γ-AlO composite catalysts prepared by HPtCl ⋅ 6HO (CPA) or Pt(NH)(NO) (PTA) as Pt precursors. The aim of this study is to validate findings from Transmission Electron Microscopy (TEM) by using characterization techniques that sample larger amounts of catalyst per measurement. Quantitative X-ray Photoelectron Spectroscopy (XPS) showed that the catalyst prepared with CPA led to a significantly higher Pt/Al atomic ratio than the catalyst prepared with PTA confirming that the 1-2 nm sized Pt nanoparticles in the former catalyst were located on the open and mesoporous γ-AlO component, whereas they were located in the micropores of zeolite Y in the latter. By using infrared spectroscopy, a shift in the absorption band maximum of CO chemisorbed on Pt nanoparticles was observed, which can be attributed to a difference in electronic properties depending on the support of the Pt nanoparticles. Finally, model hydrogenation experiments were performed using β-phenylcinnamaldehyde, a reactant molecule with low diffusivity in zeolite Y micropores, resulting in a 5 times higher activity for the catalyst prepared by CPA compared to PTA. The combined use of these characterization techniques allow us to draw more robust conclusions on the ability to control the location of Pt nanoparticles by using either CPA or PTA as precursors in zeolite/γ-AlO composite catalyst materials.
研究了以氯铂酸六水合物（CPA）或硝酸铂（PTA）为铂前驱体制备的Pt/沸石Y/γ -Al₂O₃复合催化剂中铂纳米颗粒的位置。本研究的目的是通过使用每次测量能对大量催化剂进行取样的表征技术来验证透射电子显微镜（TEM）的研究结果。定量X射线光电子能谱（XPS）表明，用CPA制备的催化剂比用PTA制备的催化剂具有显著更高的Pt/Al原子比，这证实了前一种催化剂中1 - 2纳米大小的铂纳米颗粒位于开放的中孔γ -Al₂O₃组分上，而在后一种催化剂中它们位于沸石Y的微孔中。通过红外光谱法，观察到吸附在铂纳米颗粒上的CO的吸收带最大值发生了位移，这可归因于取决于铂纳米颗粒载体的电子性质差异。最后，使用β -苯基肉桂醛进行了模型加氢实验，β -苯基肉桂醛是一种在沸石Y微孔中扩散率较低的反应物分子，结果表明用CPA制备的催化剂的活性比用PTA制备的催化剂高5倍。这些表征技术的联合使用使我们能够就以CPA或PTA作为沸石/γ -Al₂O₃复合催化剂材料的前驱体来控制铂纳米颗粒位置的能力得出更可靠的结论。
