H2PtCl6-derived Pt nanoparticles on USY zeolite: A qualitative and quantitative electron tomography study

Abstract

a b s t r a c tThe structural details of a bifunctional Pt/USY catalyst were studied using electron tomography. As a part of a fundamental study on the synthesis of Pt/USY catalyst, H 2 PtCl 6 precursor was used for the impregnation of USY zeolite support as a source of negatively charged PtCl 6 2À ions in order to restrict interaction with acidic sites of USY zeolite. After heat treatments, it was visualized in 3D that some Pt particles were 3-4 nm in size, while the majority maintained the size of 1.2-1.5 nm which corresponds to the diameter of the zeolite Y micropore cavities (1.2 nm). Electron tomography further revealed that 3-4 nm Pt particles seem to be entrapped in the zeolite crystal, without preferential location in mesopores or at the surface of the crystals. Quantitative image analysis provided the diameters (compared with EXAFS results) and the nearest neighbor distances of hundreds of imaged Pt particles.

Control and Impact of Metal Loading Heterogeneities at the Nanoscale on the Performance of Pt/Zeolite Y Catalysts for Alkane Hydroconversion

“… 57 For impregnated samples, however, it is well known that nearly all metal nanoparticles reside in the zeolite crystals. 52 , 90 Even if that would not be the case and a significant part of Pt would be on the outer surface of the zeolite crystals, this would have a positive influence on the catalytic performance. 40 , 91 Additionally, in industry, binders are used to make strong catalyst extrudates and the Pt metal can also be deposited on this binder.…”

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

“…A comparison of the size values with those obtained by EXAFS was also included in that work. 497 Ricolleau and colleagues published a paper on the comparison of ET and HRTEM slicing methods as tools to measure the thickness of CoPt NPs deposited on a substrate. Regarding thickness measurements, ET presents several advantages over HRTEM, although the precision of the experiments obtained by these two techniques is similar.…”

Effect of reduction on Co catalyst active phase highlighted by an original approach coupling ASAXS and electron tomography

“…Individual or supported nanoparticles can also be characterized by electron tomography: in the first case, the morphology (including faceting) of the particles is sought [23], in the latter case, the location inside the support can be explored. As an example, Zecevic et al examined the location of Pt in USY zeolites crystals, showing the presence of Pt particles inside the microporosity [29,29,30]. If the contrast between the nanoparticles and the support is too weak in bright field TEM, chemical sensitive techniques have to be used [21].…”