PNNL

Abstract

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 FeOx/metal nanostructures in which the concentration of oxide species adjoining metal domains is maximal. The synthesis involves reductive deposition of Rh or Pt and oxidation of Fe2+ from magnetite (Fe3O4). We discovered a parallel dissolution and adsorption of Fe2+ onto the metal, yielding inverse FeOx-coated metal nanoparticles. This new nanostructure exhibited an activity more than 20 times faster than simple supported metal nanoparticles in selective CO2 reduction. By enabling a simple way to control the surface functionality of metal particles, our approach is not only scalable but also enables a versatile new palette for catalyst design.