TRANSITION METALS AS DOPANT IN NICKEL BORIDES. THEIR CATALYTIC EFFECT ON HYDROGENATION REACTIONS

D. ACOSTA; N. RAMÍREZ; E. ERDMANN; H. DESTÉFANIS; E. GONZO.

CATALYSIS TODAY

Elsevier

Lugar: New York- USA; Año: 2007 vol. 133 p. 49 - 55

0920-5861

Nickel borides doped with first transition elements (Cr, Mn, Fe, Co, Cu, Zn) MNiB, 4 % w/w, and prepared with the same method as NiB, were used in the glucose and the nitrobenzene hydrogenation reactions. The MNiB amorphous catalysts were prepared by chemical reduction of borane-tetrahydrofurane (BH3-THF) complex with nickel salts and metallic (Cr, Mn, Fe, Co, Cu, Zn) salts in aprotic solvent (THF anhydrous), which gives bimetallic borides. Different techniques were used to characterize these materials. The MNiB amorphous structure was verified by XRD. The results show the behavior of bimetallic borides follow a pattern related to the nature of the dopant metal. The oxidation stability, magnetic susceptibility and catalytic effect are correlated with parameters of each dopant metal. DRX results an amorphous structure. SEM studies show the same spongy-morphology in all cases. The logarithm of the ratio between bimetallic boride specific rates over nickel boride for nitrobenzene hydrogenation follow a linear relation with respect the same relation for glucose hydrogenation. These results mean that the effect on the free activation energy is the same for both reaction systems. This effect could be related with electronic modifications on nickel boride due to the dopant metal.