Exceptional high-temperature stability through distillation-like self-stabilization in bimetallic nanoparticles

Abstract

Metal nanoparticles with precisely controlled size and composition are highly attractive for heterogeneous catalysis. However, their poor thermal stability remains a major hurdle on the way towards application at realistic technical conditions. Recent progress in this area has focused on nanostructured oxides to stabilize embedded metal nanoparticles. Here, we report an alternative approach that relies on synthesizing bimetallic nanoparticles with precise compositional control to obtain improved high-temperature stability. We find that PtRh nanoparticles with sufficiently high Rh content survive extended calcination at temperatures up to approximately 850 degrees C without significant sintering. For lower Rh content, sacrificial self-stabilization of individual nanoparticles through a distillation-like process is observed: the low-melting-point metal (Pt) bleeds out and the increasing concentration of the high-melting-point metal (Rh) leads to re-stabilization of the remaining nanoparticle. This principle of thermal self-stabilization should be broadly applicable to the development of multi-metallic nanomaterials for a broad range of high-temperature applications.

Cu‐Si Nanocable Arrays as High‐Rate Anode Materials for Lithium‐Ion Batteries

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Interplay between pore size and nanoparticle spatial distribution: Consequences for the stability of CuZn/SiO2 methanol synthesis catalysts

“…The design and synthesis of catalysts with enhanced stability requires a fundamental understanding of the factors governing metal particle growth [25,26,27,28]. The influence of catalyst composition and structure on metal particle growth has been previously studied for several systems [29,30,31,32].…”

High temperature stability of platinum nanoparticles on few-layer graphene investigated by In Situ high resolution transmission electron microscopy

“…The sample was further heated from room temperature to 430 °C , stabilized for 2 h and the change in metal particle size was then analyzed. Statistical TEM analysis indicates that after the thermal annealing at 430 °C , the size of most of the Pt particles did not exceed 5 nm, a limiting value defining the so-called mitohedrical region in which pronounced nanosize effects are found [27,28].…”