Andrews, Joy C.; Weckhuysen, Bert M.

ChemPhysChem (2013), 14(16), 3655-3666 CODEN: CPCHFT; ISSN: 1439-4235. English.

A review. Heterogeneous catalysts often consist of an active metal (oxide) in close contact with a support material and various promoter elements. Although macroscopic properties, such as activity, selectivity and stability, can be assessed with catalyst performance testing, the development of relevant, preferably quant. structure-performance relationships require the use of advanced characterization methods. Spectroscopic imaging in the hard X-ray region with nanometer-scale resolution has very recently emerged as a powerful approach to elucidate the hierarchical structure and related chem. of catalytic solids in action under realistic reaction conditions. This X-ray-based chem. imaging method benefits from the combination of high resolution (.apprx.30 nm) with large X-ray penetration and depth of focus, and the possibility for probing large areas with mosaic imaging. These capabilities make it possible to obtain spatial and temporal information on chem. changes in catalytic solids as well as a wide variety of other functional materials, such as fuel cells and batteries, in their full complexity and integrity. In this concept article we provide details on the method and setup of full-field hard X-ray spectroscopic imaging, illustrate its potential for spatiotemporal chem. imaging by making use of recent showcases, outline the pros and cons of this exptl. approach and discuss some future directions for hierarchical functional materials research.