Multilayered Materials Comprising Mesoporous Thin Films and Metal Nanoparticles

Abstract

A novel composite material based on metal nanoparticles (NP) and mesoporous thin films (MPTF), more specifically bilayers of MPTF with a submonolayer of NP deposited between them is introduced. By controlling the deposition conditions, it is possible to build a variety of multilayers including MPTF with different compositions (TiO2, SiO2) and pore sizes (templated with cetyltrimethylammonium bromide, F127, Brij 58) and NP of different characteristics and sizes (Au spheres, Au decorated SiO2). By means of 2D small angle X-ray scattering, transmission electron microscopy, UV–vis spectroscopy, and ellipsometric porosimetry it is demonstrated that NP and MPTF retain their structure and properties within the new material. Importantly, the NP remain accessible for further reactions, a feature that is established by Au overgrowth. Interestingly, the extent of Au growth depends on the mesoporous size and the position of the MPTF with respect to the NP. This new architecture allows the NP to be in direct contact with two different chemical environments and, as a consequence, opens up the possibility to control identity and size of the molecules that can reach them. Thus, the obtained materials may be applied in the development of highly specific sensors and catalysts, in which spatial position plays a fundamental role.