Surface effect of the MgCl2 support in Ziegler–Natta catalyst for ethylene polymerization: A computational study

Abstract

Ziegler–Natta (Z–N) catalyst is a remarkable catalyst for olefin polymerization in the petrochemical industry. However, the role of each component remains unclear because of the complicated constituents and structures. MgCl2 is a suitable support for Z–N catalyst, which can improve the activity and stereoselectivity during olefin polymerization and achieve large-scale production of polyolefin under mild conditions. In exploring the role of MgCl2 in the Z–N catalyst system for ethylene polymerization, the stable surface of undercoordinated Mg cations, including (104), (101), (012), (110), and (015) in α-MgCl2 and (010), (011), (012), (110), and (111) in β-MgCl2 was used to load the catalyst, and the mechanism of ethylene polymerization was simulated using the periodic density functional theory. This research found that the curve between the energy barrier of ethylene polymerization and the surface energy of MgCl2 represented the volcano plot, which was consistent with the Sabatier principle. The surface energy of the support was an effective descriptor for predicting catalyst performances.