Inverse iron oxide/metal catalysts from galvanic replacement.

Key chemical transformations require metal and redox sites in proximity at interfaces; however, in traditional oxide-supported materials, this requirement is met only at the perimeters of metal nanoparticles. We report that galvanic replacement can produce inverse FeO/metal nanostructures in which the concentration of oxide species adjoining metal domains is maximal. The synthesis involves reductive deposition of rhodium or platinum and oxidation of Fe from magnetite (FeO). We discovered a parallel dissolution and adsorption of Fe onto the metal, yielding inverse FeO-coated metal nanoparticles. This nanostructure exhibits the intrinsic activity in selective CO reduction that simple metal nanoparticles have only at interfaces with the support. By enabling a simple way to control the surface functionality of metal particles, our approach is not only scalable but also enables a versatile palette for catalyst design.