Preparation of metal oxide/zeolite core-shell nanostructures

Here we report the synthesis of metal oxide/zeolite core-shell nanostructures by adsorption of zeolite nanoparticles on metal oxide particles followed by secondary hydrothermal growth. The metal oxide surface was first modified by a layer by layer self-assembly of polyelectrolyte, subsequently attached zeolite nanoparticles on the surface through coulombic attractions. By monitoring the zeta potential vs pH, this method can be applied for different metal oxides, such as ZnO and TiO₂, with versatile surface properties. A secondary growth method was applied to form a thin, continuous, and well-intergrown shell outside the metal oxide nanoparticles. Although the secondary growth condition is highly alkaline and corrosive along with significantly different from the coating conditions, the growth of the zeolite nanoparticles is fast enough to form a closed layer before the coating falls apart as well as avoid damage to the metal oxide core particles. Such a metal oxide/zeolite core-shell nanostructure can be used as tiny membrane reactor and may find potential applications in the field of metal oxide based heterogeneous catalysis.