Superior moderate-strength Pd–Pt/Al-based composite tailored for dehydrogenation of perhydroacenaphthene

Abstract

Pd–Pt-based catalysts are promising for the dehydrogenation of perhydroacenaphthene (PHAN) molecules, yet their effectiveness is hampered by strong adsorption of the product C12H8 and limitations under extreme conditions. Herein, utilizing a relational model involving d-band center, sub-surface coverage, and H atom and C12H8 adsorption energies, the most dehydrogenation-prone crystal facet was identified. Following this, employing Mulliken charge and Sabatier principle, we screened positively charged Pd–Pt/111_O2(Al) surface with moderate interaction strength through the calculation of interaction energy between the chosen Pd–Pt surface and thermally stable MgAl2O4(111) terminal surfaces. Crucially, an extensive examination into reaction mechanisms, microkinetics, and the variation in interaction strength between support and active components at 873.15 K and 3 MPa was conducted. It was observed that the rate-determining step for PHAN molecules on the Pd–Pt/111_O2(Al) surface was C12H19* + * → C12H18* + H*, with a rate of 2.57 × 10-23 s−1. The dehydrogenation of C12H10 to C12H8 proved more favorable than from C12H20 to C12H10, with the latter strengthening support and active components, unlike the weakening effect of the former. This work offers essential foundational support for the development of excellent performance catalysts and the dehydrogenation process of superior heat sink fuels.