Molecular traffic jam

The cover of the February issue of Angewandte Chemie features the manuscript “Host-guest geometry in pores of zeolite ZSM-5 spatially resolved with multiplex CARS spectromicroscopy” by AMOLF postdoc Katrin Domke.

Zeolites are commonly employed catalysts that enhance the rate of chemical reactions, and steer the reactions in the desired direction. The observed reactivity of zeolites is based on the complex interplay between reagent molecules and the inside of the catalyst's well-defined nanoporous network. Like a key needs to fit snugly in order to open a lock, molecules have to assume a certain geometry inside the pores to be converted efficiently into the desired chemical product.

Researchers from Amolf and from the University of Utrecht have achieved an exceptionally detailed look at the local geometry of reagent molecules in zeolite pores using advanced nonlinear spectromicroscopies. The molecules align head-to-tail, forming micrometer long chains inside the catalyst pores, equivalent to cars stuck in a traffic jam between Amsterdam and Mainz (Germany).

Further advancing their research, the team presented the first spectroscopic evidence of reaction product formation directly inside the catalyst pores. The product yield was ca. 5 times higher inside the zeolite than outside, i.e. determined off-line after rinsing, and considerable spatial inhomogeneities in particle reactivity were observed.
The results are of fundamental importance for the advancement of catalysis research aimed at efficient and cheap design of next generation catalysts.

Contact:
Dr. Katrin Domke, +31207547100, k.domkeATamolf.nl
Prof.dr. Mischa Bonn, (06131 379-161, bonnATmpip-mainz.mpg.de)

Reference:
K.F. Domke, J.P.R. Day, G. Rago, T.A. Riemer, M.H.F. Kox, B.M. Weckhuysen, M. Bonn
Host-guest geometry in pores of zeolite ZSM-5 spatially resolved with multiplex CARS spectromicroscopy
Angewandte Chemie International Edition (2012), published online: 08-12-11 . DOI: 10.1002/anie.201106447

K.F. Domke, J.P.R. Day, G. Rago, T.A. Riemer, M.H.F. Kox, B.M. Weckhuysen, M. Bonn
Tracing Catalytic Conversion on Single Zeolite Crystals in 3D with Nonlinear Spectromicroscopy
Journal of the American Chemical Society 134 (2012) 1124-1129. DOI: 10.1021/ja2088025