Facile Synthesis of Ru Nanoboxes with a Hexagonal Close‐Packed Structure by Templating with Ag Nanocubes and Their Catalytic Properties

Abstract Noble‐metal nanoboxes offer an attractive form of nanomaterials for catalytic applications owing to their open structure and highly efficient use of atoms. Herein, we report the facile synthesis of Ag−Ru core−shell nanocubes and then Ru nanoboxes with a hexagonal close‐packed (hcp ) structure, as well as evaluation of their catalytic activity toward a model hydrogenation reaction. By adding a solution of Ru(acac) 3 in ethylene glycol (EG) dropwise to a suspension of silver nanocubes in EG at 170 °C, Ru atoms are generated and deposited onto the entire surface of a nanocube. As the volume of the Ru III precursor is increased, Ru atoms are also produced through a galvanic replacement reaction, generating Ag−Ru nanocubes with a hollow interior. The released Ag + ions are then reduced by EG and deposited back onto the nanocubes. By selectively etching away the remaining Ag with aqueous HNO 3 , the as‐obtained Ag−Ru nanocubes are transformed into Ru nanoboxes, whose walls are characterized by an hcp structure and an ultrathin thickness of a few nanometers. Finally, we evaluated the catalytic properties of the Ru nanoboxes with two different wall thicknesses by using a model hydrogenation reaction; both samples showed excellent performance.