Effects of Heavy Rare Earth Elements on Properties of Amorphous NiB Alloy Catalyst

Gas-phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth elements on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TPR and TPD were used to characterize the bulk and the surface properties of the alloys, respectively. The results indicate that the addition of a small amount of heavy rare earth (HRE) elements obviously improves the activity, thermal stability and sulfur resistance of amorphous NiB alloy. The HRE can alter H2 adsorption bond strength, increase the surface area of active nickel and the number of active centers over the surface of NiB alloy and it also can decrease the activation energy of NiB alloy for benzene hydrogenation. There are four kinds of adsorbing sites over the surface of NiB and NiBRE, only three kinds of them have concerned with the reaction.