【摘要】 用脉冲微反技术以苯加氢反应为探针,研究了重稀土元素Dy,Ho,Er,Tm,Yb,Lu对非晶态NiB合金催化剂的加氢和抗硫性能的影响。用X射线衍射(XRD)、差示扫描量热(DSC),CO化学吸附法、程序升温还原(TPD)及程序升温脱附(TPD)等方法对催化剂进行了表征。结果表明,重稀土可提高NiB合金的热稳定性、活性和抗硫性。其原因为稀土RE对NiB合金的电子及几何效应共同作用的结果导致活性中心数增多、活性镍表面积增大,吸氢量明显增大而吸氢强度变弱;同时降低了非晶态NiB合金催化剂催化的苯加氢反应的活化能。非晶态NiB和NiBRE合金催化剂上有4种氢吸附中心,其中3种吸附中心参与了表面反应。更多还原

【Abstract】 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 resist ance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TPR and TPD and were used to characterize the surface properties of the alloys. The resu lts indicate that the addition of a small amount of heavy rare earth elements ob viously improves the activity and sulfur resistance of amorphous NiB alloy becau se of the electronic and structural interaction between NiB alloy and RE. It can alter H2 adsorption bond strength, increase the surface area of active nickel and the number of active sites over the surface of NiB alloy and it also can de crease the activation energy of NiB alloy for benzene hydrogenation. There are f our kinds of adsorbing sites over the surface of NiB and NiBSm, only three kinds of them have taken part in the reaction.更多还原