Polymer Template Synthesis of CuOx/Clay Nanocomposites with Controllable CuOx Formation

Metal oxides have the excellent functions including high thermal stability, electrical properties, catalytic performance, and adsorption properties of acid gases such as CO2 via the acid-base interactions. However, they suffer from low reserves, porosity control, and low adsorption efficiency per weight compared with lightweight materials including carbon and silica. To solve these issues, various methods for supporting metal oxides on porous carriers, such as decomposition-precipitation and impregnation, have been investigated, but controlling the formation of metal oxide on clay nanosheets remains as a challenge. Herein, we developed a soft-template method for supporting metal oxide (CuOx) nanoparticles on activated clay nanosheets. The intercalation of polyethyleneimine (PEI)−Cu2+ complexes between the layers of clay nanosheets followed by calcination to construct CuOx and remove the PEI templates afforded CuOx/clay nanocomposites. The constructed CuOx/clay nanocomposites had the close porosity to that of clay. Tuning the Cu2+/PEI ratio in PEI−Cu2+ complex allowed to control CuOx states (loadings, particle sizes, etc.). Tuning of the supporting conditions allowed constructing a structure suitable for CO2 uptake. These findings will contribute to the development of the material science of metal oxide nanoparticles and their hybrid materials in diverse fields including CO2 adsorbents, energy devices, and catalysts.