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本文用程序升温还原(TPR)方法研究了硅铝(SiAl)和铈Y型分子筛(CeHY)催化剂上沉积镍钝化前后的还原情况。发现在TPR图上沉积镍的还原峰温为600～610℃,比一般的NiO要高290～300℃。在Sb钝化剂处理过的催化剂的TPR图上.在5G0～530℃和700℃左右出现二个还原峰。在Sn钝化剂处理过的催化剂的TPR图上,在510～550℃和700～760℃左右也出现二个还原峰。TPR图形的差别表明在沉积镍和钝化剂之间存在强的相互作用。或者形成了合金。TPR的实验结果与以前得到的XRD测量数据完全一致。本文还用电子顺磁共振(ESR)方法研究了沉积镍的还原过程,发现在平衡条件下沉积镍在400～500℃之间开始还原。ESR图谱上有一宽而对称的谱线(g(?)2.160)和一弱的诺线(g(?)1.965),前者相当于金属镍的f.m.r.吸收谱线,后者相当于Ni~+离子的顺磁吸收谱线。700℃还原以后少量Ni~+离子依然存在于催化剂样品中。锑和锡钝化剂处理以后,样品的ESR图谱发生变化。
In this paper, the temperature reduction (TPR) method was used to study the reduction before and after nickel deposition on the SiAl and CeHY catalysts. It is found that the reduction peak temperature of Ni deposited on TPR is 600 ~ 610 ℃, 290 ~ 300 ℃ higher than that of NiO. On the TPR plots of Sb deactivator-treated catalysts, two reduction peaks appeared at temperatures of 5G0 ~ 530 ℃ and 700 ℃. On the TPR plot of Sn passivator treated catalyst, two reduction peaks appeared at 510 ~ 550 ℃ and 700 ~ 760 ℃. The difference in TPR patterns shows that there is a strong interaction between the deposited nickel and the passivating agent. Or formed an alloy. The experimental results of TPR are completely consistent with the previously obtained XRD measurement data. In this paper, the electron-paramagnetic resonance (ESR) method was also used to study the reduction process of nickel deposit. It was found that the nickel deposition started to decrease between 400 and 500 ℃ under equilibrium condition. The ESR spectrum has a broad symmetry line (g (?) 2.160) and a weak noxious line (g (?) 1.965), the former corresponding to the fmr absorption line of metallic nickel, which corresponds to the Ni ~ + ion Paramagnetic absorption line. After the reduction at 700 ℃, a small amount of Ni ~ + ions still exist in the catalyst samples. Antimony and tin passivation treatment, the sample ESR changes.