TITLE: Carbonaceous Overlayers Precursors on Multimetallic Catalysts and Their Relation to Catalytic Activity and Deactivation: Final Report.

AUTHOR: P. A. Montano;   B. R. Cooper.

INST.  AUTHOR: West Virginia Univ., Morgantown. Dept. of Physics.

SPONSOR: Department of Energy, Washington, DC.


PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1984,  140p.



We describe the details of implementation of the Film Linearized Muffin-Tin Orbital (FLMTO) method of Krakauer and Cooper for slab geometries. Using the constrained wave functions as described by Krakauer and Cooper, we get consistently good results except for the work function.  We describe an alternate method that we have also implemented to improve the work function. This discards the Plane Wave Orbitals while striving to improve the quality of the basis functions for describing the vacuum behavior without increase in matrix sizes. We find the quality of results poorer. Therefore, in the Appendix, we suggest a way of increasing the variational freedom by removing the constraint on the Plane Wave Orbitals.  The experimental section deals with three different systems. The first consists in the study of a stable phase of fcc-Fe and their crystallographic and electronic properties. This is a novel an unique material which is characterized by a remarkable difference in electronic properties from the most commonly form of iron (bcc). The second part deals with a detailed investigation of the metal/support interaction using a MgO single crystal as the support and Fe as the Fischer-Tropsch catalyst. We performed a complete study of the electronic properties of this system and characterized the surface carbonaceous deposits by means of the Surface Extended Energy Loss Fine Structure (SEE LFS) Technique.  The third part, a mixed metal Fischer-Tropsch catalyst Fe/Mn was studied by x-ray diffraction, Moessbauer spectroscopy and EXAFS. We determined the behavior of the catalysts on two supports silicate and alumina and identified the phases of Fe/Mn before, during and after reaction in CO/H sub 2 . The following section give a detailed description of the experimental work. (ERA citation 13:000434)