Phase-Dependent Anchoring Effect of Al–OH on Pt Clusters for Enhanced Propane Nonoxidative Dehydrogenation

The Al2O3 support plays a crucial role in the fabrication of high-performance PDH catalysts. Understanding the impact of different Al2O3 phases on supported Pt species is essential for enhancing the catalytic performance, which remains a challenge. Herein, a series of Al2O3 supports with γ, θ, and α phases are synthesized via a hydrothermal method, and the corresponding Pt/Al2O3 catalysts are prepared using an incipient-wetness impregnation method. The γ-Al2O3 support effectively anchors Pt clusters on the surface, whereas Pt nanoparticles tend to aggregate on the θ and α-Al2O3 support. The Pt/Al2O3-750 catalyst with the γ phase exhibits the highest yield of 13.6% among all Pt/Al2O3 catalysts and demonstrates efficient stability after reaction–regeneration cycles. The abundant Al–OH hydroxyl groups on the γ-Al2O3 support are primarily responsible for anchoring Pt species, as opposed to the commonly assumed coordinatively unsaturated AlV sites. The obtained insight into the role of the Al2O3 phase and Al–OH hydroxyl groups can provide a novel idea for the future design of Pt-based catalysts.