Crystal Facet Structure Dependence and Promising Pd-Pt Catalytic Materials for Perhydroacenaphthene Dehydrogenation

Designing an effective Pd-Ptcatalytic materialwith excellentcatalytic performance for perhydroacenaphthene (PHAN) dehydrogenationis a great challenge. In this work, in order to explore the crystalfacet structure over the bimetallic Pd-Pt catalyst on the dehydrogenationperformance of PHAN, the surface compositions of two kinds of Pd (Pt)atoms with different coverage on Pd modulated Pt (PdPt) and Pt modulatedPd (PtPd) catalysts were designed and studied by means of densityfunctional theory (DFT). Through the investigation of the reactionpath of PHAN dehydrogenation on PdMLPt-(111) and PtMLPd-(111) surfaces, it was found that PdMLPt-(111)was advantageous to PHAN dehydrogenation (E (a) = 2.317 eV). This was attributed to a lower energy barrier, morestable dehydrogenation products, and the fact that Pd doping broughtPt(111) close to the Fermi level. Apparently, Pd modulated Pt catalysthas a broad application prospect in the dehydrogenation of PHAN. Inthe process of optimizing the PdPt morphology, a method for selectingthe minimum active unit of PdPt catalysts with different ratios wasproposed, that is, the most stable active unit: rhombus structurewas determined according to the surface formation energy. Moreover,we correlated the relationship among the number of H atoms removed,adsorption energy, surface charge, activation energy, reaction energy,and surface coverage, and obtained the important parameters to predictthe performance of PdPt catalyst in PHAN dehydrogenation system: surfacecharge and d-band center. Finally, the essentialcorrelativity among Pd-Pt surface characteristics, catalyticPHAN activity, and adsorption energy was constructed; that is, therelationship model among d-band center, H atom, andproduct C12H8 adsorption energy was established.This work opens a new simultaneous path to improve the catalytic performanceof Pd-Pt-based catalytic materials for PHAN dehydrogenation,which can be achieved by regulating the rhombic active units of Ptmodulated by Pd.

Automated summary

This study investigated the mechanism of Pd-Pt alloy catalyst in the dehydrogenation of PHAN using density functional theory. The results showed that PdPt-(111) catalyst had advantages in PHAN dehydrogenation due to lower energy barrier and more stable dehydrogenation products. In addition, a method for selecting the minimum active unit of PdPt catalyst was proposed, and a correlation model among Pd-Pt surface characteristics, catalytic activity, and adsorption energy was established.