Opportunities in the design of metal@oxide core-shell nanoparticles

Nanoparticles composed of metallic cores encapsulated in oxide shells emerged in the last decade as an attractive class of nanocomposite materials due to their high stability and unique properties provided by the high contact area between the metal and oxide components. Diverse metal-oxide interactions in metal@oxide core@shell nanoparticles enable tuning their electronic structure, spectroscopic properties, and surface reactivity for applications in sensing, electrochemistry, batteries as well as thermal and photocatalysis. Herein, we review the recent literature on the synthesis, characterization, simulations, and applications of metal@oxide nanocomposites. In particular, we discuss how the properties of metal@oxide nanoparticles can be tuned for a given application by changing the size of the metal core, the thickness and porosity of the oxide shell, as well as their composition, e.g. by alloying the core or doping the shell. Understanding of structure-property relations in metal@oxide systems provides vast opportunities for the rational design of advanced metal@oxide nanocomposites, making this class of materials promising for a wide range of applications.