Atomic Layer Deposition of γ-Al₂O₃ on Hexagonal Boron Nitride: A Hybrid Support for Metallocene Catalysts

Hexagonal boron nitride (hBN), also known as white graphene, has recently gained larger attention due to its unique physical and chemical properties. Owing to its excellent thermal conductivity and stability, hBN has been reported as an effective filler in many polymers. This study explores the potential of hBN as a catalyst support and filler for olefin polymerization. We report the atomic layer deposition (ALD) of γ-Al₂O₃ on hydroxyl-functionalized hBN. The alumina precursor, methylaluminoxane, showed high selectivity, depositing Al species only on the B-OH sites, while B−O-O−B sites remained unreacted. The hBN/γ-Al₂O₃ hybrid was characterized by Fourier transform infrared (FTIR) spectroscopy, X-Ray diffraction and transmission electron microscopy (TEM). The deposition of the aluminum over the hBN sheets was confirmed. The hBN/γ-Al₂O₃ was used as a support for metallocene catalysts. The supported catalyst complex was highly active and produced ethylene-propylene polymers with molecular weights up to 10 times higher, as demonstrated by gel permeation chromatography (GPC).