Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

Abstract

A novel synthesis procedure for the preparation of the hierarchical zeolite materials with MFI structure based on the carbon templating method with in situ generated carbon template is presented in this study. Through chemical vapour deposition of coke on nickel nanoparticles supported on silica oxide, a carbon-silica composite is obtained and exploited as a combined carbon template/silica source for zeolite synthesis. This approach has several advantages in comparison with conventional carbon templating methods, where relatively complicated preparative strategies involving multistep impregnation procedures and rather expensive chemicals are used. Removal of the carbon template by combustion results in zeolite single crystals with intracrystalline pore volumes between 0.28 and 0.48 cm 3 /g. The prepared zeolites are characterized by XRD, SEM, TEM and physisorption analysis. The isomerization and cracking of noctane is chosen as a model test reaction and the mesoporous zeolite catalyst is found to exhibit higher activity than the conventional catalyst.

Methanation of Carbon Dioxide over Zeolite‐Encapsulated Nickel Nanoparticles

“…Over the years, much research has therefore been devoted to strengthen metal–support interactions by optimizing the catalyst composition . Furthermore, highly stable Ni catalysts have been obtained by optimizing the three‐dimensional distribution of nanoparticles in ordered mesoporous materials and by encapsulation of nanoparticles in porous inorganic shells . In particular, Laprune et al .…”

Enhanced Catalytic Performance of Zn‐containing HZSM‐5 upon Selective Desilication in Ethane Dehydroaromatization Process

“…Enhancing mass transfer could increase accessibility to the active sites and facilitate transfer of molecules out of the crystal, thereby inhibiting further conversion of desired products into coke species. Nowadays, the leading materials to improve catalytic performance by minimizing the mass transfer limitation are hierarchical zeolites consisting of both micro and mesopores that facilitate transport of bulky molecules . In general, there are two approaches to synthesis hierarchical zeolites: either by direct synthesis using hard/soft templates or post‐modification such as alkali/acid treatment .…”

Mesoporous MEL, BEA, and FAU zeolite crystals obtained by in situ formation of carbon template over metal nanoparticles

“…3 and Table 1 that mesoporous ZSM-11 and Beta zeolite samples obtained by novel method using in-situ-generated carbon template have standard pore volumes and are characterized by large surface areas [28,30]. However, mesoporous Zeolite Y sample has a rather moderate degree of Please do not adjust margins Please do not adjust margins [34] and as it is shown in our previous work [26], it can be improved by varying process parameters in 2.6.1. The different and a quite moderate degree of mesoporosity in Zeolite Y compared to ZSM-11 and Beta could be due to the much different procedure for the preparation of the synthesis gel.…”

“…Therefore, several preparative strategies have been developed in the attempt to improve the performance of zeolites in catalysis: the synthesis of zeolites with extra-large pores [8][9][10][11], direct synthesis of zeolite nanocrystals [12][13][14][15][16][17], by exfoliating layered zeolites [18,19], and by introducing mesopores in the microporous materials through templating strategies [7, 20 -22] or demetallation processes [4,7,[23][24][25]. Recently, a novel synthesis procedure for the preparation of mesoporous MFI-type material based on the carbon templating method with an in-situ-generated carbon template was reported by our group [26]. The mesoporous zeolite crystals combine the shape-selectivity, hydrothermal stability, and high acidity typical for conventional zeolites with highly efficient transport of reactants and products typical for mesoporous materials [7].…”

“…In the presented approach a cheap and available silica source -silica gel (SiO 2 ) is used. The carbon template is generated in situ by decomposition of methane, which results in the formation of large amounts of coke around the silica supported nickel nanoparticles [26]. The formation of coke over metal nanoparticles is a well-known phenomenon for a range of catalytic reactions that is frequently investigated [31].…”