Zeolite Y Crystals with Trimodal Porosity as Ideal Hydrocracking Catalysts

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

“…The bimodal particle size distribution points to a preferred size of $3.5 nm for the larger particles. This diameter coincides with that of two neighboring supercages of zeolite Y and also with the size of small mesopores that emerge upon base leaching of USY zeolite [11]. We speculate that the local properties of the zeolite Y framework favor generation of ''defects'' of a characteristic size of at least 3 nm.…”

“…These larger Pt particles can be accommodated in the cavities formed by merging two neighboring supercages of zeolite Y. The characteristic sizes of $ 3 nm were also observed in an earlier study [11], where base leaching of zeolite Y caused generation of small mesopores in the zeolite crystals. The number-average Pt particle diameter of 2.2 nm obtained by image analysis fits very well with the 1.9 nm derived from EXAFS analysis also considering the bimodal particle size distribution.…”

“…having a high surface-to-volume ratio) and well distributed throughout the support, and in addition be preferably located in the vicinity of the acid sites of the support. Moreover, the porosity of the support has a large influence on the molecular diffusion and hence catalyst performance [7][8][9][10][11][12][13][14].…”

“…Next to application in hydroisomerization and hydrocracking [11,15,16], Pt and Pd supported zeolite Y catalysts have been recently proposed as possible candidates for hydrodesulfurization [12,13]. Numerous studies have been performed in order to investigate the influence of different heat treatments on Pt dispersion and on the nature of the Pt species [17][18][19][20][21][22].…”

“…However, measuring Pt diameters manually and determining their location from common TEM micrographs is very labor intensive and susceptible to errors due to the overlapping features in 2D projections. To overcome these shortcomings, electron tomography (ET, also referred to as 3D-TEM) has been successfully employed for visualizing the interior/ 3D morphology of a number of catalysts [11,[25][26][27][28][29][30][31][32][33][34]. The threedimensional reconstructions (intensity maps) that are obtained by ET can be subjected to automated image processing which enables quantitative analysis of the catalyst features [30][31][32][33][34].…”