J. Phys. Colloques
Volume 47, Numéro C8, Décembre 1986EXAFS and Near Edge Structure IV
|Page(s)||C8-277 - C8-280|
J. Phys. Colloques 47 (1986) C8-277-C8-280
EXAFS STUDY OF NICKEL TETRACARBONYL AND Ni-CLUSTERS IN ZEOLITE YT. BEIN1, 2, S.J. McLAIN1, G. D. STUCKY1, G. WOOLERY2, D.E . SAYERS3 et K. MOLLER4
1 E.I. Dupont de Nemours and Company, Central Research and Development Department, Experimental Station, Wilmington, DE 19898, U.S.A.
2 Mobil Research and Development Corporation, Paulsboro Research Laboratory, Paulsboro, NJ 08066, U.S.A.
3 Department of Physics, North Carolina State University, Raleigh, NC 27695, U.S.A.
4 Department of Chemical Engineering, University of Delaware, Newark, DE 19716, U.S.A.
Adsorption and thermal decomposition of Ni(CO)4 in the cage system of zeolite Y have been studied with EXAFS, electron microscopy and IR spectroscopy. Ni(CO)4 is adsorbed as an intact molecule in both cation-free zeolite Y and NaY. Symmetry changes of the molecule in NaY are assigned to the formation of Na+ --OC-Ni bridges. Thermal treatment of the Ni(CO)4/NaY adduct leads to loss of CO concomitant with the formation of a binodal Ni phase. A major part of the Ni forms clusters with diameter between 0.5 and about 1.5 nm, in addition to larger crystallites (5-30 nm), sticking at the outer surface of the zeolite matrix. The Ni-Ni scattering amplitude indicates increasing average particle size with increasing temperature.