Acidic Site Regulation of the Supported Pt–Cu Alumina Catalyst with the Bimetallic Synergistic Effect Achieved High Catalytic Selectivity in Dehydrogenation of Perhydrodibenzyltoluene

Dibenzyltoluene (DBT) is one of the most promising hydrogen storage media of liquid organic hydrogen carriers, but it is difficult to solve the problems of low catalyst selectivity and deactivation caused by the high byproducts of dehydrogenation. This study designed the Pt_2.0Cu_0.1/Al₂O₃-900 °C catalyst that could balance the high activity and selectivity of the dehydrogenation of perhydrodibenzyltoluene (18H-DBT). The proposed methodology, involving controlled acid pretreatment of bimetallic Pt-Cu catalysts, exhibited superior spatial confinement characteristics compared to the series of pure Pt and Pt-Cu catalysts. This optimized protocol effectively modulates the acid site distribution by decreasing total acidity and reducing strong acid site density in the highly dispersed nanoparticles catalyst. Comparative spectroscopic and microscopic analyses (X-ray photoelectron spectroscopy/high-resolution transmission electron microscopy/Py-DRIFT) demonstrated that the electronic structure modification and diminished strong metal-support interaction (strong metal-support interactions) in Pt-Cu bimetallic catalysts, when benchmarked against pure Pt systems, collectively contribute to the inhibition of excessive side reactions. Kinetic and mechanistic studies reveal that the substrate of 18H-DBT was more susceptible to the unique electronic effect and geometric effects of Pt-Cu, leading to a reduction in the reaction energy barrier.