Understanding the Synthesis of Alumina Supported Metal Catalysts at an Atomic Level
EMSL Project ID
48308
Abstract
Despite the important role of supported metal catalysts in industrial processes there are significant gaps in our understanding of the atomic level transformations during their synthesis, in particular calcination. However, insight at this level is necessary to fully optimize the specificity of synthesis techniques. The proposed work will provide this insight by using a suite of analytical techniques including NMR, x-ray absorption, and IR spectroscopy, ETEM, STEM, helium ion microscopy and TGA-DSC-MS. Complementary modeling studies will be performed to rationalize the observations during these experiments. Alumina supported Pt, Ni, Co, and Ru catalysts will be prepared using dry impregnation and controlled adsorption. We will elucidate how different impregnation or adsorption methods provide a different spatial distribution of metal precursors on the surface and how this translates to differences in the size distribution of metal particles on the catalyst. In addition to mapping the distribution of metal precursors on the surface, we will determine the temperature at which the precursors decompose and the metal particles become mobile. We will also elucidate when and where metal particles bind to specific sites on the alumina surface. It is important to point out that the preferred binding sites may only be formed during calcination. Due to the complex interplay of transformations of the metal precursors and the support a comprehensive, fundamental study on the preparation supported metal catalysts is overdue. The ultimate goal of our work is to provide recommendations on how synthesis methods for supported metal catalysts can be refined.
The requested resources at EMSL will enable us to address these questions in much more detail than we would be able to with the available resources at Georgia Tech. Specifically, solid state 27Al and 1H MAS NMR spectra with superior resolution will be acquired using high magnetic fields (? 20 T) and fast spinning rates (25-40 kHz). ETEM will allow for in-situ studies on the formation and transformation of catalytic surfaces during calcination and reduction, while STEM and helium ion microscopy will provide sufficiently high resolution to map metal precursors on the surface. With the requested computing resources it will be possible to perform complementary modeling studies to rationalize the experimental observations.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2014-10-01
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Okolie C, YF Belhseine, Y Lyu, M Yung, MH Engelhard, L Kovarik, E Stavitski, and C Sievers. 2017. "Conversion of Methane into Methanol and Ethanol over Nickel Oxide on Ceria-Zirconia Catalysts in a Single Reactor." Angewandte Chemie 56(44):13876-13881. doi:10.1002/anie.201704704
Okolie C., Y. Lyu, L. Kovarik, E. Stavitski, and C. Sievers. 2018. "Coupling of Methane to Ethane, Ethylene and Aromatics over Nickel on Ceria-Zirconia at Low Temperatures." ChemCatChem 10, no. 12:2700-2708. PNNL-SA-131737. doi:10.1002/cctc.201701892