Electronic metal–support interaction tailored by Ru cluster size for low-temperature reversible H2 storage via toluene hydrogenation

Abstract

The precise control of metal nanoparticle size offers a powerful yet underexploited approach for engineering the electronic structure of catalytic active sites beyond geometric design. Herein, we demonstrate that the Ru cluster size on CeO₂ is a decisive factor in tailoring the electronic metal–support interaction (EMSI). By varying the Ru size from 0.7 to 1.6 nm, we achieve systematic modulation of electron donation from CeO₂ to Ru, which in turn non-monotonically shifts the charge transfer and d-band center. This electronic tuning optimizes toluene adsorption and H₂ dissociation, resulting in exceptional performance for low-temperature hydrogenation of toluene, a critical step for reversible H₂ storage. The optimal Ru/CeO₂ catalyst (1.4 nm) delivers a turnover frequency of 15 871 h⁻¹ at 50 °C, nearly one order of magnitude higher than current benchmarks. This work establishes metal cluster size as a fundamental descriptor for rationally tailoring interfacial charge transfer in diverse heterogeneous systems.