Effect of γ-Al2O3 on the catalytic and surface properties of NiB alloy

The pulse microreaction technique was used to examine the effect of addition of alumina on the catalytic and surface properties of amorphous NiB alloy. Gas-phase hydrogenation of benzene was chosen as probe reaction. The structure, composition and crystallization were determined by XRD, ICP and DSC, respectively. The surface properties were characterized by TPR and TPD. The results indicated that addition of alumina increased the activity, thermal stability, and sulfur resisting property of NiB alloy. Comparing the two kinds of methods of addition, impregnation was superior to mechanically mixing. The result of the dynamic studies on pulse reaction showed that benzene hydrogenation over amorphous NIB alloy, NiB+Al2O3, NiB-Al2O3 followed Langmuir-Hinshwood model, the sequence of activation energy over the samples was as follows: E-a(NIB) > E-a(NiB+Al2O3) > E-a(NiB-Al2O3). The results of TPR and TPD indicated that addition of alumina decrease the types of absorbing sites, but increase the amount of absorbtion obviously.