Copper Core–Porous Manganese Oxide Shell Nanoparticles

Abstract

Core–shell nanoparticles, especially those with nanoporous oxide shells, exhibit chemical and physical properties that are distinct from those of the bulk materials due to the atomic-level proximity and morphology of the core and shell atoms. Here, we demonstrate a wet-chemical method for the synthesis of Cu core (∼6.1 nm)–porous Mn₃O₄ shell (∼3.4 nm thick) nanoparticles. Various characterization techniques, including synchrotron radiation-based small-angle X-ray scattering (SAXS) and X-ray absorption near edge structure (XANES) tools, confirm the core–shell structure. Both the chemical and physical properties of these Cu-based nanoparticles are influenced by the Mn₃O₄ shell. For example, the magnetic properties of the core–shell particles are found to be similar to those of Mn₃O₄ nanoparticles reported in the literature. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results demonstrate that these materials are catalytically active for CO adsorption and hydrogenation.