Development of Magnetically Responsive Multifunctional Nanoparticles for Catalytic Reduction Reactions

Abstract

Introduction of multiple functionalities at the nanoscale is a major challenge in the area of nanoscience. Typically, one carries out different kinds of modifications to the nanoparticle systems for the realization of diverse functional traits. One of the most attractive functional trait deals with the emergence of intelligently “responsive” behavior from a nanoparticle system. We endeavor into the regime of incorporating advanced functionalities by integrating two attractive nanoscale properties: plasmonics and magnetism. The multifunctional nanohybrid system comprised of Gold (Au) and magnetite (Fe3O4) NPs, which imparted the plasmonic and magnetic properties respectively. The work undertaken in this thesis is summarized into three parts. Firstly, we summarize our efforts along with the challenges that we faced in our attempts to synthesize desired Fe3O4/Au core/shell NPs. Secondly, we present an alternative synthetic strategy for attaching plasmonic Au NPs on magnetic Fe3O4 NPs using an amorphous silica shell as the binder. Thirdly, we explore the multifunctional properties of these Au@Fe3O4/SiO2 core/shell NPs in catalysis. The metallic and plasmonic properties of Au NPs in the nanohybrid were used for the catalytic reduction of substrates; whereas the magnetic property of Fe3O4 was conveniently used for the separation and recyclability of the catalyst. The Au@Fe3O4/SiO2 core/shell NPs exhibited catalytic activity comparable to the commonly used benchmark citrate stabilized Au NP catalyst. At the same time, the multifunctional catalyst developed by us showed superior recyclability and additional advantage of ease of separation.