Formation of PdFe alloy clusters in zeolite Y

Journal Article · Wed Nov 03 23:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100146a028· OSTI ID:5526022

Xu, L; Lei, G D; Sachtler, W M.H. ^[1]; Cortright, R D; Dumesic, J A ^[2]

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1. Northwestern Univ., Evanston, IL (United States)
2. Univ. of Wisconsin, Madison, WI (United States)

Reduction of ion-exchanged PdFe/NaY with H[sub 2] at 773 K results in the formation of Fe[sup 2+] ions and PdFe alloy clusters; no Fe[sup 0] is formed by reducing Fe/NaY. The extent of Pd-enhanced reduction of Fe[sup 2+] to Fe[sup 0] decreases with increasing proton concentration in the zeolite. Data obtained by Moessbauer spectroscopy, ferromagnetic resonance, and FTIR of adsorbed CO indicate prevalent formation of PdFe alloy clusters. Temperature-programmed reduction (TPR) and desorption (TPD) show the extent of Fe reduction and the reoxidation by zeolite protons of Fe[sup 0] in bimetal particles. An average composition of Pd[sub 16]Fe and Pd[sub 10]Fe[sub 3] was found for the reduced clusters in PdFe/NaHY and neutralized PdFe/NaY, respectively. No [alpha]-Pd hydride is formed with PdFe[sub x] under conditions where this hydride is prevalent for unalloyed Pd clusters. The propensity to form Pd hydride is restored by oxidative leaching of the Fe atoms from the bimetallic clusters. A strong ferromagnetic resonance signal from PdFe[sub x] particles isolated in different zeolite cages and containing only one or two Fe atoms suggests that Pd atoms surrounding an Fe atom become polarized. 71 refs., 8 figs., 4 tabs.

• OSTI ID: 5526022
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:44; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ALLOYS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
DESORPTION
ELEMENTS
EXPERIMENTAL DATA
FERROMAGNETIC RESONANCE
HYDROGEN
INFORMATION
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON ALLOYS
MAGNETIC RESONANCE
MATERIALS
MINERALS
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PALLADIUM ALLOYS
PLATINUM METAL ALLOYS
REDUCTION
RESONANCE
SILICATE MINERALS
SORPTION
SPECTRA
SPECTROSCOPY
SYNTHESIS
ZEOLITES