Controlled metal nanomaterials for catalysis applications

Abstract

This proposal focuses on the development of facile, versatile and environmentally friendly methodologies for obtaining bimetallic and trimetallic nanomaterials displaying well-defined and controllable size, shape, composition, structure (solid or hollow interiors) and architecture (nanodendrites and core-shell systems). Specifically, we will focus on three classes of materials: i) trimetallic nanoshells composed of Ag-PtAu, Ag-PdAu, and Ag-PdPt; ii) Ag-M and Au-M nanodendrites, where M = Pd, Pt, Rh, and Au; and iii) Ag-M and Au-M core-shell systems. While the trimetallic nanoshells will be produced by a galvanic replacement approach, the nanodendrites and core-shell systems will be obtained through seeded growth. Then, bimetallic nanoshells composed of Ag-Au, Ag-Pd and Ag-Pt (developed in our last FAPESP project) as well as the materials described in i), ii) and iii) will be employed as heterogeneous catalysts for a variety of model reactions relevant in the context of chemical synthesis. In particular, we will focus on the hydrogenation of 4-nitrophenol, three-component coupling via C-H activation, Suzuki coupling, and oxidation of benzyl alcohol and terpenes. As the nanomaterials produced in this project will have well controlled features, this will enable the systematic investigation of how the catalytic activities (percentages of conversion and selectivity) are dependent upon the physicochemical parameters that define the nanomaterial such as size, composition, structure and architecture. In a last stage of this proposal, we plan to initiate studies on the use of the developed nanomaterials in plasmon enhanced catalytic processes. (AU)