A Metal-on-Metal Growth Approach to Metal–Metal Oxide Core–Shell Nanostructures with Plasmonic Properties

Abstract

Hybrid core–shell nanoparticles integrate the material properties from individual components; however, the synthesis of core–shell nanoparticles with dissimilar materials remains challenging. In this work, we applied a metal-on-metal thin film growth approach to control the conformal deposition of non-precious metal shells on the Cu-based metal cores to form core–shell structures of metal–metal oxide hybrids (M–M′O x , where M = AuCu3 or Cu, M′ = Fe, Mn, and Ni). The deposition kinetics were controlled by a temperature-regulated thermal decomposition of zerovalent transition metal complexes. It is predicted that the conformal deposition can be promoted by keeping the initial deposition temperature close to the thermal decomposition temperature of the zerovalent precursors. The mechanisms of strain reduction and interdiffusion facilitate conformal deposition over island growth in the synthesis with slow reaction kinetics. This study provides insightful guidance to metal-on-metal growth in solution at the nanoscale and thus the seed-mediated approach to hybrid core–shell structures. The optical properties of these metal–metal oxide hybrids were investigated experimentally and interpreted by theoretical simulations. Despite damping effects, the plasmonic properties of these Cu-based core-metal oxide shell structures may have the potential to enable plasmon-enhanced applications.

Bridging Colloidal and Electrochemical Nanoparticle Growth with In Situ Electrochemical Measurements

“…Just as an electrochemical synthesis of Au nanorods inspired the development of some of the first colloidal syntheses for shaped nanoparticles, the now well-established field of colloidal synthesis is ideally positioned to inspire advances in electrochemical nanoparticle growth. Many research groups, including our own, have contributed to the development of a broad range of techniques for controlling colloidal nanoparticle shape using reaction kinetics, molecular and ionic additives, secondary metals, seed structure, and other means. ,,,,− For example, surfactants and their corresponding counterions are common components of colloidal growth solutions because of their ability to modify crystal growth pathways through preferential adsorption onto particular facets in addition to their primary role of stabilizing particles against aggregation. ,− However, while additives are often present in electrochemical plating solutions, they are not used deliberately to define particle morphology. Using strategies from colloidal approaches in combination with the ability to facilely tune applied current or potential in electrodeposition opens exciting pathways for moving well beyond the existing limitations of both synthetic methods.…”

Hydrous ruthenium oxide triggers template-free and spontaneous growth of metal nanostructures

“…[1][2][3][4][5][6] Such nanomaterials exist in numerous designs, including core-shell, yolk-shell, Janus, dots-on-nanorods, dots-in-nanotubes, nanobranched, and heterodimer. [7][8][9][10][11][12][13] Among various chemical compositions, metal oxide supported multicomponent nanomaterials have gained immense importance due to their enhanced and unanticipated catalytic activities originating from multiple phenomena, encompassing strong metal support interactions, modied electronic band structures, the availability of plasmonic hot electrons, and improved durability. [14][15][16][17][18] Both physical and chemical methods are used to synthesize metal oxide-supported noble metals.…”