Catalytic Properties of Glassy and Crystalline Transition Metal Alloys Produced by RSP
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CATALYTIC PROPERTIES OF GLASSY AND CRYSTALLINE TRANSITION METAL ALLOYS PRODUCED BY RSP
S.S. Mahmoud+, D.A. Forsyth and B.C. Giessen Department of Chemistry and Materials Science Division, Barnett Institute, Northeastern University, Boston, MA 02115
ABSTRACT of Pd 80 Si 2 0 1 Pd 3 5 Zr65, selectivity The catalytic activity and their ribbons in Fe 8 5 B 1 5 and Cu5 0 Zr 5 Q alloy Ni 3 0 Zr 70 , Fe 4 0 Ni 4 0 B2 0 , studied in the hydrogenation of crystalline states were amorphous and and dehydrogenation of methylcyclohexane 1-hexene and phenylethyne, Pd 8 0Si 2 0 was found to be the most active dehydrocyclization of n-heptane. Most alloys were more active amorphous of the alloy catalysts studied. however, the catalytic selectivities of than in the crystalline state; the amorphous and crystalline states of each alloy were identical.
INTRODUCTION subject of studies glasses have been the Recently, metallic concerning the potential for their use as hydrogenation catalysts in the hope that their properties might differ from those of the currently used The crystalline metal catalysts in their activities and selectivities. and might be found between amorphous that differences expectation crystalline catalysts of the same composition is based on the results of studies by Somorjai and others who have found the catalysis of some reactions
to be
"structure
sensitive"
(1).
Thus,
Yokoyama
et
al.
have
studied the catalytic activity of fifteen amorphous alloy ribbons based on Fe-Ni containing P and/or B as glass forming additives with respect to their catalytic effect in the hydrogenation of CO; they found that Cl and C3 hydrocarbons were the principal products, and noted that the catalytic amorphous alloys was several to several hundred times activity of the higher than that of the crystalline alloys of the same composition (2,3). Previously, Smith et al. studied the catalytic activity and selectivity of splat cooled amorphous Pd 8 0 Si 2 0 with respect to the deuteration of they found that the amorphous splats were more selective cyclododecene; than crystalline palladium in catalyzing addition rather than exchange (4). The work reported in the present paper is part of an extended study of the catalytic properties of melt spun alloy ribbons with respect to an early account of this work was hydrogenation and related reactions; The use of NMR as an analytical tool in some of these given in Ref. 5. 6; a note on additional hydrogenation studies is reported in Ref. catalysts is in preparation.
. Communication No. + Present Address:
278 from the Barnett Institute Department of Chemistry, Brandeis University, Waltham, MA 02235
Mat. Res. Soc. Symp. Pro
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