Evaluating the Dehydrogenation Performance of Cyclohexane on Pt-Skin AgPt3(111) and Ag3Pt(111) Surface Slabs: A Density Functional Theory Approach

Abstract

The development of highly effective dehydrogenation catalysts presents significant potential for storing hydrogen solutions with favorable economic advantages. In this study, we examined the dehydrogenation of cyclohexane on Pt-skin AgPt₃(111) and Ag₃Pt(111) surfaces in comparison with that on a Pt(111) pristine surface by applying density functional theory. We assessed the performance of various exchange–correlation functionals (PBE, BEEF-vdW, optPBE-vdW, and PBE-D3) in predicting the adsorption energy of cyclohexane on Pt–AgPt₃(111), Pt–Ag₃Pt(111), and Pt(111) surfaces and compared them to the experimental data. Through systematic calculations, we analyzed the electronic and structural properties of catalysts, adsorption energies of cyclohexane and intermediate molecules on various Ag–Pt alloy surfaces, surface charge distribution, dehydrogenation processes, and the effect of Ag concentration on its activity. The findings indicate that an increase in the Ag content leads to a closer shift of the d-band center of the Pt atom toward the Fermi level, moving from −2.31 to −1.81 eV. This shift increases surface charge accumulation. This gradual accumulation enhances the adsorption of cyclohexane. Notably, the dehydrogenation of cyclohexane on Pt-skin Ag₃Pt exhibited a lower reaction energy, with a value of 1.31 eV compared to the pristine Pt(111) catalyst. This study revealed that the Pt-skin Ag₃Pt(111) catalyst exhibits enhanced performance for the dehydrogenation of cyclohexane, which should stimulate additional experimental studies.