In situ synchrotron-based IR microspectroscopy to study catalytic reactions in zeolite crystals

In recent years a number of in situ microspectroscopic techniques have been explored to investigate catalytic reactions taking place in heterogeneous catalysts in a timeand space-resolved manner.[1–8] These spectroscopic methods have proven to be very successful in elucidating valuable structure–function relationships for acid–base catalytic reactions. In the work of Roeffaers et al. fluorescence microscopy has been applied to demonstrate the crystal-face-dependent catalysis on layered double hydroxide (LDH) materials.[1] By this elegant approach one can track interconversion processes of individual molecules in catalytic solids and obtain indirect data on the chemical nature of the reaction products formed, provided they display fluorescence. For example, the red shift of the emission bands of specific carbocations formed was used to visualize the degree of oligomerization of cyclic alcohols in individual H-ZSM-5 zeolite particles.[3]