A series of in situ hot stage experiments using transmission electron microscopy (TEM) were studied to directly observe the transition of a Ni-MOF to Ni nanoparticles wrapped in carbon (Ni-NPC) over temperatures ranging from ambient temperature to 700 °C. Ni-NPC-600 displays high catalytic activity in 4-nitrophenol reduction and high conversion, even after 10 cycles.

•Mesoporous and Al-rich MFI zeolite was synthesized without organotemplate (MFI-SDS).•MFI-SDS are assembled with rod-like nanocrystals with almost the same aligned direction.•The space between nanocrystals forms the mesoporosity in MFI-SDS.•MFI-SDS exhibits excellent catalytic properties in cumene cracking.Mesoporous zeolites have been paid much attention recently due to their excellent mass transfer and high activity for bulky molecules as well as unique shape selectivity, but their syntheses usually require the presence of organic templates. Here, we report organotemplate-free synthesis of mesoporous and Al-rich MFI zeolite in the presence of the zeolite seeds (MFI-SDS). The MFI-SDS crystals are assembled with rod-like nanocrystals having almost the same aligned direction, confirmed by the sample transmission electron microscopy (TEM). The space between nanocrystals forms the mesoporosity in the sample, supported by N2 sorption isotherms. 27Al MAS NMR spectroscopy and ICP analysis show that the MFI-SDS has abundant tetrahedral Al species in the zeolite framework, giving the Si/Al ratio at 9.5. Catalytic tests in cumene cracking show that the MFI-SDS exhibits higher catalytic activities and longer catalyst life than conventional ZSM-5 zeolites synthesized in the absence (ZSM-5-OTF) or presence of organic template, TPA+ (ZSM-5-TPA). The excellent catalytic performance should be assigned to the combined contribution of the presence of both mesoporosity and rich tetrahedral Al species in the MFI-SDS. These features would be critically important for industrial applications of MFI zeolite catalysts in the future.Mesoporous and Al-rich MFI zeolite assembled with rod-like nanocrystals having almost the same aligned direction is successfully synthesized in the absence of any organic templates, which exhibits higher catalytic activities and longer catalyst life in cumene cracking than conventional ZSM-5 zeolites due to the combined contribution of mesoporosity and abundant Al sites in the zeolite.

As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure was determined and further confirmed by Rietveld refinements of powder X-ray diffraction. HRTEM gave direct imaging of the channels.

Mesoporous zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity. We report here the successful synthesis of mesoporous aluminosilicate zeolite Beta from a commercial cationic polymer that acts as a dual-function template to generate zeolitic micropores and mesopores simultaneously. This is the first demonstration of a single nonsurfactant polymer acting as such a template. Using high-resolution electron microscopy and tomography, we discovered that the resulting material (Beta-MS) has abundant and highly interconnected mesopores. More importantly, we demonstrated using a three-dimensional electron diffraction technique that each Beta-MS particle is a single crystal, whereas most previously reported mesoporous zeolites are comprised of nanosized zeolitic grains with random orientations. The use of nonsurfactant templates is essential to gaining single-crystalline mesoporous zeolites. The single-crystalline nature endows Beta-MS with better hydrothermal stability compared with surfactant-derived mesoporous zeolite Beta. Beta-MS also exhibited remarkably higher catalytic activity than did conventional zeolite Beta in acid-catalyzed reactions involving large molecules.

A series of in situ hot stage experiments using transmission electron microscopy (TEM) were studied to directly observe the transition of a Ni-MOF to Ni nanoparticles wrapped in carbon (Ni-NPC) over temperatures ranging from ambient temperature to 700 °C. Ni-NPC-600 displays high catalytic activity in 4-nitrophenol reduction and high conversion, even after 10 cycles.