硼的钝镍作用及机理研究

STUDY ON THE MECHANISM OF NI PASSIVATION BY B

通过MAT ,TPR ,XRD等实验方法和量化计算系统研究了某种无毒硼盐对FCC沸石催化剂上沉积镍的钝化作用和机理。结果表明 ,由于氧化硼和氧化镍在FCC再生条件下反应生成Ni2 B2 O5,增加了Ni2 + 的LUMO能量 ,使镍在FCC反应条件下更难被还原 ,因此 ,添加适量的BPN可以有效地抑制FCC沸石催化剂上镍的脱氢生焦活性 ,达到钝镍的目的。

The mechanism of nickel passivation by the non-toxic B salt (named BPN) has been investigated, in which the methods of NAT, TPR and XRD were used, combined with quantum chemistry calculation. The results show that the new compound Ni 2B 2O 5 forms after the addition of BPN to Ni-deposited zeolite under the condition of FCC regeneration. Because the energy of LUMO of Ni 2B 2O 5 is much higher than that of NiO, Ni 2B 2O 5 is more difficult to be reduced than NiO under the condition of FCC reaction. Therefore, the dehydrogenation activity of NiO is inhibited. This is the nickel passivation mechanism of BPN.