INSITU STUDIES OF THE DEHYDRATION OF ZEOLITIC CATALYSTS BY TIME-RESOLVED ENERGY-DISPERSIVE X-RAY ABSORPTION-SPECTROSCOPY

The merits of employing the energy-dispersive mode for recording the dynamics of the structural changes accompanying the thermal activation of an as-prepared catalyst are illustrated by a time-resolved investigation of the dehydration of an Ni2+-exchanged Na+ zeolite Y catalyst (see Couves, Jones, Thomas, and Smith, Adv. Mater. 1990, 2, 181). EXAFS data for a model metallic nickel catalyst, collected in 500 ms, are also shown. These yield quantitatively reliable structural information, thus demonstrating the feasibility of conducting routine, dynamic studies of heterogeneous catalysts and a variety of other material under operating conditions. © 1990 American Chemical Society.