Institute of Technology Characterization Facility

Related Links


Upcoming Events

  • Check back again, events will be listed as information becomes available.

A Structural Resolution Cryo-TEM Study of the Early Stages of MFI Growth

Sandeep Kumar, Zhuopeng Wang, R. Lee Penn and Michael Tsapatsis
Journal of the American Chemical Society, 130 (51), 17284, 2 Dec 2008

high-resolution cryo-TEM image
Figure: A high-resolution cryo-TEM image of a representative crystal in synthesis sol aged for 220 days at room-temperature.  Fast Fourier transform (FFT), shown in the inset, indicates the crystal to be oriented either along [100]- or [010]-axis.  The bright and dark dots within the high-lighted perimeter represent the straight or sinusoidal pores of the MFI framework structure.  Image obtained using the FEI Tecnai G2 F30 Cryo-TEM.
In this communication, the authors present a cryogenic transmission electron microscopy (cryo-TEM) study on precursor sols prior to and during the early stages of MFI formation.  Cryo-TEM images with structural resolution were obtained and yielded new insights in MFI growth.  The importance of this study is two-fold.  First, the authors provide evidence supporting the recently proposed mechanism of evolution of nanoparticles followed by aggregative crystal growth while adding a new element.  The new element is the formation of predominantly amorphous aggregates before MFI crystallization and points to the importance of intra-aggregate rearrangements in nucleation and growth.  Second, the authors demonstrate that electron-beam sensitive materials such as zeolites can be imaged by cryo-TEM with structural resolution in their parent sols.  Similar studies for other zeolites under different conditions may reveal useful structural information for the understanding of hydrothermal nucleation and growth.

Abstract and article at Journal of the American Chemical Society


CharFac Offers New Instrument

The CharFac is pleased to announce a new TEM PicoIndenter (Hysitron), capable of nanomechanical testing inside of a transmission electron microscope (TEM).  CharFac is one of the first facilities in the world with this capability  With the PicoIndenter, quantitative force-displacement curves can be time correlated to the corresponding TEM movie of the stress-induced deformation processes.  The combination of CharFac’s high-end FEI TEMs and this analytical tool will enable researchers to witness the nanoscale structural changes corresponding to observed force and displacement transients.  Some example applications are direct observation of depth-sensing indentations, quantitative compression testing, and defect formations such as dislocations, stacking faults, twins, etc.

 

Main Office

12 Shepherd Labs
100 Union St. S.E.
Minneapolis, MN 55455

Phone:  (612) 626-7594
Fax:  (612) 625-5368
Email: