ACTIVATION MECHANISM OF AMORPHOUS Ni_xZr100_-x ALLOYS DURING CO/H₂ REACTION AND PREPARATION METHOD OF POROUS AMORPHOUS ALLOY CATALYSTS

Abstract

The hydrogenation of carbon monoxide over amorphous Ni_xZr_100-x (x = 91, 67, 50, 40, 33) alloys was investigated. During the reaction, amorphous Ni₅₀Zr₅₀ and Ni₆₇Zr₃₃ alloys spontaneously increased their catalytic activity by more than two orders of magnitude. The formation of porous structure within the amorphous bulk alloy is mainly responsible for the activity increase. The development process of the porous structure, which finally leads the alloys to segregate into nickel species and ZrO₂, can be stopped by decreasing the reaction temperature. This process can, therefore, expose fresh alloy surfaces for use in catalytic reactions and enlarges the specific surface area of amorphous alloy. It is shown that NiZr alloys are catalytically more active than pure Ni for the hydrogenation of carbon monoxide.