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 Ru cluster size on CeO2 is a decisive factor in tailoring the electronic metal-support interaction (EMSI), enabling programmable charge transfer and d-band center position. By varying Ru size from 0.7 nm to 1.6 nm, we achieve systematic modulation of electron donation from CeO2 to Ru, which in turn non-monotonically shifts the Ru 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, representing an order-of-magnitude improvement over current benchmark. This work opens a general catalyst design in which metal cluster size serves as a fundamental descriptor to rationally tailor interfacial electronic structure for diverse heterogeneous systems.