In-situ scanning transmission X-ray microscopy of catalytic solids and related nanomaterials.

The present status of in-situ scanning transmission X-ray microscopy (STXM) is reviewed, with an emphasis on the abilities of the STXM technique in comparison with electron microscopy. The experimental aspects and interpretation of X-ray absorption spectroscopy (XAS) are briefly introduced and the experimental boundary conditions that determine the potential applications for in-situ XAS and in-situ STXM studies are discussed. Nanoscale chemical imaging of catalysts under working conditions is outlined using cobalt and iron Fischer-Tropsch catalysts as showcases. In the discussion, we critically compare STXM-XAS and STEM-EELS (scanning transmission electron microscopy-electron energy loss spectroscopy) measurements and indicate some future directions of in-situ nanoscale imaging of catalytic solids and related nanomaterials.