Dual-Stabilization Strategy for Inhibiting Metal Nanoparticle Sintering Over Ceria Surfaces

Ceria supported noble metals are important commercial catalysts, however, the long-term stability suffering from metal particle sintering still challenges the practical benefits. This work determines the favorable migration pathway of supported Pt particles over CeO₂ surface as well as three distinct trends of isomorphous substitution in modulating the metal-support interactions (MSIs), via extensive ab-initio molecular dynamics (AIMD) simulations and density functional theory calculations with on-site Coulomb interaction correction. We find that, while several dopants (Ti, Ge, Sn) enhance the MSI upon contact with metal particles, Ge shows additionally an intriguing MSI weakening effect in the distant region, stemming from the reduction of tetravalence Ge into off-lattice Ge²⁺ cation (Ge⁴⁺ + 2Ce³⁺ → Ge²⁺ + 2Ce⁴⁺). Integrating with the dynamic bury-and-expose migratory structure inspires us to propose an effective sintering-resistance strategy of constructing dual-stabilization "deeper well and taller wall" migration energetics, simply by manipulating Ge doping content within an estimated threshold (roughly to be one tenth of Pt). Such approach can remarkably stabilize surface Pt particles with migration energy consumption being elevated by 1.80 eV and exhibit broad applicability to other supported metals (e.g., Rh/CeO₂), giving rise to excellent stability even under harsh experimental conditions of H₂ atmosphere at 800 °C.