Atomic Layer Deposition of Al ₂ O ₃ Regulates the Pt/ZSM‐23 Metal‐Acid Balance to Promote Efficient Hydroisomerization of n‐Hexadecane

ABSTRACT Designing a bifunctional catalyst to achieve efficient hydroisomerization of long‐chain alkanes is essential for producing high‐performance fuel and lubricant base oils. In this study, a series of Pt‐xAl 2 O 3 /ZSM‐23 catalysts was prepared by depositing varying amounts of Al 2 O 3 onto ZSM‐23 supports via atomic layer deposition (ALD), followed by loading Pt. Additionally, the IM‐Pt/ZSM‐23 catalyst was prepared via the impregnation method. Their catalytic performance was systematically evaluated in the hydroisomerization of n‐hexadecane (n‐C 16 ). The results demonstrate that an appropriate amount of Al 2 O 3 deposition facilitates the anchoring and dispersion of the Pt precursor, modulates surface acidity, and optimizes proximity between metal and acid sites, thereby regulating the metal‐acid balance and leading to improved catalytic activity and isomer selectivity. Consequently, the Pt‐10Al 2 O 3 /ZSM‐23 catalyst exhibited the best performance, maintaining a high isomer yield even at conversions exceeding 80%. In contrast, both IM‐Pt/ZSM‐23 and Pt/ZSM‐23 exhibited lower catalytic activity and isomer selectivity. This work provides valuable insights for designing highly active and selective catalysts for the hydroisomerization of long‐chain alkanes.