Engineering (Er-)O-mediated hydrogen spillover via Er-doped Pt/Al2O3 for efficient hydrogen release from methylcyclohexane

Er doping in Al 2 O 3 creates (Er–)O sites that promote hydrogen spillover. • The dual-site catalyst breaks the activity–stability trade-off in MCH dehydrogenation. • Er doping weakens Pt H adsorption and lowers the kinetic barrier of the rate-determining step. • The strategy extends to La and Y dopants, offering a general platform for advanced LOHC catalysts. The development of highly efficient and stable catalysts is essential for advancing methylcyclohexane (MCH)-based liquid organic hydrogen carrier (LOHC) technology, yet the performance of alumina-supported Pt-based catalysts for MCH dehydrogenation is often constrained by an inherent activity-stability trade-off. Here, we demonstrate that this limitation can be overcome by constructing a synergistic dual-site configuration comprising Pt nanoparticles and atomically dispersed (Er-)O sites. Supported on Er-doped Al 2 O 3 , uniformly sized Pt nanoparticles exhibit an exceptionally high hydrogen production rate of 2966 mmol∙g Pt −1 ∙min −1 at 300 °C (Pt/5Er-Al), outperforming most alumina-supported Pt catalysts. Remarkably, this catalyst shows excellent long-term stability, maintaining a hydrogen purity exceeding 99.9% even under high temperature and high space velocity conditions. Combined structural characterizations, kinetic studies, in situ H D exchange DRIFTS, and density functional theory calculations reveal that the doping upshifts the Pt d-band center and reduced Pt electron density, weakening H adsorption and promoting H spillover to adjacent (Er-)O sites. This synergy maintains low hydrogen coverage on Pt, lowering the kinetic barrier of the rate-determining step and accelerating H 2 evolution. The hydrogen spillover strategy mediated by atoms doped in alumina demonstrated herein opens a new avenue for designing advanced alumina-based dehydrogenation/hydrogenation catalysts. The incorporation of Er into Pt/Al 2 O 3 catalyst enhances hydrogen spillover, thereby significantly promoting the dehydrogenation activity and stability for MCH conversion. Download: Download high-res image (134KB) Download: Download full-size image