EXAFS STUDY ON ULTRAFINE NI-CO-B AMORPHOUS CATALYSTS

A series of Ni-Co-B amorphous catalysts for hydrogenation of benzene h ave been prepared in a wide composition range by chemical reduction an d their structure were studied by EXAFS. It is shown that the catalyti c activity of these Ni-Co-B amorphous alloy is affected by both nickel content and the structural disorder of the sample; the latter could b e adjusted by cobalt content of the sample. The EXAFS study also showe d that the change of the boron content of the sample has a stronger ef fect on Ni-B coordination than on Co-B coordination and there is a pre ferential coordination of boron with nickel when the composition ratio B/Ni is high.