Correlation between the crystal zize and catalytic properties of ZSM-5 zeolites

Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Brönsted acid sites

“…Powder diffractograms of the samples were recorded over a range of 2u values from 5 to 508 at a scanning rate of 58/min. The relative crystallinities of the samples were calculated basing on the intensity of the peaks of angle 2u = 22-258 in the XRD pattern [42].…”

The stability of nanosized HZSM-5 zeolite: a high-resolution solid-state NMR study

“…The Hartmann±Hahn condition was established as described in our previous paper [17]. 27 Al NMR spectra were recorded with samples spun at 10 kHz, and chemical shifts were referenced to 1% aqueous Al(H 2 O) 3 6 . 1 H MAS NMR spectra were recorded at 400.1 MHz using a single pulse excitation.…”

“…The relative crystallinity of HZSM-5 was calculated based on the intensity of the peaks of angle 2h 22°±25°in the XRD pattern [3].…”

“…They are particularly suited for catalysis applications due to these features. For example, in the conversion of methanol to hydrocarbons [3] and to ole®ns [4], as well as oligomerization of ethylene [1], nanosized HZSM-5 zeolite exhibits higher catalytic activity, less coke formation and longer life. Thus, there is a growing interest in the synthesis of nanosized zeolites [5±7].…”

In situ solid state NMR observation of the methanol-to-hydrocarbons (MTH) process over nanosized and microsized HZSM-5 zeolites

“…Sugimoto et al report that HZSM-5 zeolite consisting of small crystallites shows high selectivity for methanol conversion to C 5 hydrocarbon and less coke formation as compared with its microsized counterpart. 7 These unique effects are usually ascribed to alterations of apparent properties with particle size, that is, shortening of the active channels of the zeolites, increase in the external surface area and more accessible active sites (Brønsted acid sites).…”