Conclusion
Herein we investigated the effect of hydrogen posed over Cr-PNP
catalyzed ethylene oligomerization process using DFT calculation.
Multiple pathways were tested and compared. The introduction of hydrogen
modified the energy barriers during the oligomerization, but the exact
effect is debatable and unclear. However, hydrogen do reduce the energy
barrier to form the active center on the catalyst, enabling
proliferation of active centers. Hence, we propose that hydrogen
promotes catalyst activity by easing the formation of active centers on
the catalyst.