Mechanochemistry as a tool in the preparation of multimetallic nanomaterials

Abstract

The present project is dedicated to the solid-state mechanochemical synthesis of multimetallic NPs. The association of more than one element will vastly expand theproperty landscape of the prepared materials, consequently broadening their potential toward technological applications. The metal NPs will be synthetized using the bottom-up approach, by milling the respective metal precursors in appropriate molar ratios. The chemical reduction will take place by the addition of a solid reducing agent. The NPs will be formed by the combination of precious (Au, Ag and Pd) and other catalytically active (Ni, Cu) metals and can consist to up to five alloying elements. The type of the reducing agents (strong/mild) in the formation, elemental composition and distribution in the NPs will be studied as well as the order of the metal precursor addition (one-pot or stepwise synthesis). This will make possible to identify the dominant conditions to a successful control of the physicochemical features of the final nanostructures. The particle size and shape will be studied by TEM techniques. The atomic distribution over the NPs will be evaluated by EDS-STEM. X-ray spectroscopies (XPS and XAS) will be used to probe the local structure and the chemical environment. The crystalline phases will be identified by PXRD, and PDF can be employed to understand the formation of the NPs at the early stage. UV-VIS DRS will also be used when plasmonic metals (Au, Ag and Cu) constitute the nanostructure. In situ studies (XAS, PXRD, PDF) are also envisaged to study the mechanisms of formation of multimettalic NPs under mechanochemical conditions. The materials will be tested in model reactions to probe the structure-activity. (AU)