Preparation of site-specific cross-sections of heterogeneous catalysts prepared by focused ion beam milling

Focused ion beam (FIB) milling offers a novel approach to preparation of site-specific cross-sections of heterogeneous catalysts for examination in the transmission electron microscope (TEM). Electron-transparent sections can be obtained without the need to embed or grind the original sample. Because the specimen can be imaged in the FIB with submicrometre resolution before, during and after milling it is possible to select precisely the region from which the section is removed and to control the thickness of the section to within tens of nanometres. The ability to produce sections in this way opens the possibility of studying a range of catalyst systems that have previously been impossible to examine with the TEM.