Thermodynamically and Kinetically Stabilized Pt Clusters Against Sintering on CeO2 Nanofibers Through Enclosing CeO2 Nanocubes

Abstract

AbstractSintering is a major concern for the deactivation of supported metals catalysts, which is driven by the force of decreasing the total surface energy of the entire catalytic system. In this work, a double‐confinement strategy is demonstrated to stabilize 2.6 nm‐Pt clusters against sintering on electrospun CeO2 nanofibers decorated by CeO2 nanocubes (m‐CeO2). Thermodynamically, with the aid of CeO2‐nanocubes, the intrinsically irregular surface of polycrystalline CeO2 nanofibers becomes smooth, offering adjacent Pt clusters with decreased chemical potential differences on a relatively uniform surface. Kinetically, the Pt clusters are physically restricted on each facet of CeO2 nanocubes in a nanosized region. In situ high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) observation reveals that the Pt clusters can be stabilized up to 800 °C even in a high density, which is far beyond their Tammann temperature, without observable size growth or migration. Such a sinter‐resistant catalytic system is endowed with boosted catalytic activity toward both the hydrogenation of p‐nitrophenol after being aged at 500 °C and the sinter‐promoting exothermic oxidation reactions (e.g., soot oxidation) at high temperatures over 700 °C. This work offers new opportunities for exploring sinter‐resistant nanocatalysts, starting from the rational design of whole catalytic system in terms of thermodynamic and kinetic aspects.