Application of X-ray Ultramicroscopy to V-P-O/SiO2 CatalystsChristopher J. Kiely (Lehigh University), DMR 0709887

Rosette-type vanadium phosphorus oxide (V-P-O) catalysts for maleic anhydride production have not traditionally been used in circulating reactors because of the damage incurred by mechanical attrition. By encapsulating the V-P-O rosettes in a porous SiO2 shell, a much more robust, but still very active catalyst, can be prepared. Detailed testing and microstructural characterization of these V-P-O/SiO2 catalyst materials has been carried out as part of this Materials World Network program.

For the first time, a new X-ray projection microscopy technique (XuM) within an SEM environment has been applied to catalyst materials. This allows one to image, either in 2D projection or 3D tomography mode, the interior structure of the micron scale V-P-O/ SiO2 multi-shell catalysts without having to section or microtome them.

A montage of low magnification SEM images (row 1), X-ray ultramicrographs (row 2) and higher magnification SEM images (row 3) of the V-P-O / SiO2 precursor materials (column 1), freshly activated catalyst (column 2) and used catalyst (column 3).

Materials World Network: Catalyst Materials Synthesis at Accessible High Temperatures and Pressures

Christopher J. Kiely (Lehigh University), DMR 0709887

International Research CollaborationResearchers from Cardiff University (UK) are preparing complex oxide catalysts (e.g. V-P.O) by completely new synthesis routes. Lehigh University (USA) are using state-of-the-art X-ray and electron microscopies to analyze the micro- and nanostructures of these materials.

Educational OutreachPart of the MWN collaboration involves swapping personnel between the UK and USA institutions. A senior Cardiff researcher has already attended the renowned Lehigh Microscopy School on SEM and EDS analysis.

New Technique ApplicationX-ray ultramicroscopy (XuM) has been applied for the first time to 1-20m V-P-O/SiO2 catalyst particles. Imaging the internal structure of particles in this size regime is usually problematical since they are too thick for TEM and SEM gives only surface morphology. We have demonstrated that XuM is an effective non-destructive technique for this solving problem and has general applicability in the field of particulate analysis.

Gatan-XRT XuM system