(495g) Systematic Design of Highly Efficient Catalysts for Hydrogen Release in MCH/Tol-Based LOHC System

Liquid Organic Hydrogen Carriers (LOHCs) represent a promising hydrogen storage solution due to their high hydrogen capacity, reversibility, and compatibility with existing infrastructure. Despite these advantages, the endothermic hydrogen release process requires high temperatures, necessitating catalyst optimization to enhance efficiency. This study addresses the critical need for improved catalytic performance in LOHC dehydrogenation by exploring strain engineering as a novel approach to enhance Pt-based catalysts. While previous research has established the importance of adsorbate-catalyst surface alignment in catalytic efficiency, the systematic manipulation of strain to optimize this alignment remains unexplored for methylcyclohexane (MCH) dehydrogenation.

Through density functional theory (DFT) calculations, we demonstrate that tensile strain significantly enhances the catalytic performance of Pt surfaces for MCH dehydrogenation. Our key finding reveals that while MCH adsorption remains constant across strain conditions due to its physisorption nature, toluene (TOL) adsorption strengthens under tensile strain, creating more favorable reaction energetics. We observed a strong linear relationship (BEP relationship, R²=0.99) between total reaction energy and activation energy of the rate-determining step. Building on these insights, we designed and evaluated Pt₃M@Pt core-shell structures with various M elements, enabling precise control over lattice strain at the Pt surface. Consistent with our predictions, structures inducing tensile strain exhibited reduced activation barriers for the rate-determining step. To validate our computational predictions, we successfully synthesized representative core-shell catalysts and measured their hydrogen release performance. The results demonstrated enhanced hydrogen evolution rates from tensile strained Pt surfaces, confirming the feasibility of strain engineering in practical catalyst design. Our findings provide a fundamental understanding of strain-dependent catalytic behavior and offer a practical design strategy for next-generation LOHC dehydrogenation catalysts.