Synthesis and growth mechanism of Au@Cu core–shell nanorods having excellent antioxidative properties

Abstract

Au@Cu core-shell nanorods (NRs) were prepared using Au NRs as seeds. The resultant crystal structures were characterized using transmission electron microscopy (TEM), TEM-energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). When Cu shells were grown over Au NRs as seeds by reducing CuCl 2 •2H 2 O in an aqueous solution in the presence of hexadecylamine (HDA) and D-(+)-glucose (GLC) at 97 °C, Au@Cu NRs with {110} side facets were grown epitaxially as major side facets through a single island-growth mechanism. In this mechanism, crystal growth of Cu shells over Au core NRs starts from the formation of single semi-spherical nuclei on a wide side facet, followed by growth to neighbouring facets, with eventual full coverage by rectangular Cu shells with {110} side facets. When CuCl 2 •2H 2 O was replaced with Cu(OAc) 2 •H 2 O, layered growth of Cu shells was observed. Effects of the addition of NaCl to Cu(OAc) 2 •H 2 O show that Cl − ions play an important role in the single-island growth of Cu shells. The Au@Cu NRs exhibited much stronger antioxidative properties than spherical Cu particles.

Direct Micromolding of Bimetals and Transparent Conducting Oxide Using Metal−TOABr Complexes as Single-Source Precursors

“…Alloys and bimetals of noble metals are immensely useful for various applications such as catalysis, 1 optics, 2 and magnetism 3 over monometallic counterparts, owing to their improved performance and stability. 4 Especially, nanoparticles of bimetals and alloys, which possess high surface area, have been the most sought after because of the synergy between the metals. For instance, alloy Au–Cu nanoparticles have been preferred over Cu nanoparticles because of their enhanced oxidation stability.…”

“…For instance, alloy Au–Cu nanoparticles have been preferred over Cu nanoparticles because of their enhanced oxidation stability. 4 In catalysis, the immobilization of catalysts on the solid support attracts huge attention, as it is highly desirable for one-pot cascade reactions. 5 Conventional drop casting or spin coating of premade catalyst nanoparticles leads to the aggregation and reduction of the available active surface area.…”

One-pot preparation of nanoporous Ag-Cu@Ag core-shell alloy with enhanced oxidative stability and robust antibacterial activity

“…Metallic nanostructures possess many novel properties that are profoundly different from their bulk counterparts, which endow them wide applications in sensors, catalyst and energy 1 – 5 . As we have known that the performance of the materials with nanostructure is heavily depended on their constituents arrangement 6 , metallic core–shell nanostructures with less cost of noble metal, designed by compositing different metallic phases together, have shown better catalytic, optical, electric, and magnetic properties than monometallic nanostructures 6 – 9 . The most widely used preparation techniques of core–shell nanostructures, such as microemulsion method, epitaxial growth, microwave synthesis, electrochemical dealloying and multi-step reduction method, are limited by the complicated procedures, high costs, or difficulties to extend to large scales 1 , 10 – 14 .…”

“…But the spontaneous oxidation of copper and the relatively expensive price of silver apparently limited their applications 7 , 17 – 20 . The emergence of Ag-Cu core–shell alloy with a silver shell is expected to solve this predicament 6 , 7 , 9 . However, the simple and inexpensive method to obtain Ag-Cu core–shell nanostructured materials still remains challenging.…”

Synthesis of Carbon‐Encapsulated Cu–Ag Dimetallic Nanoparticles and Their Recyclable Superior Catalytic Activity towards 4‐Nitrophenol Reduction

“…[1][2][3] Apart from the pure enhancement of activity, dimetallic nanoparticles allow us to tune the activity reaction specifically through composition ratios and morphology tailoring. [1][2][3] Apart from the pure enhancement of activity, dimetallic nanoparticles allow us to tune the activity reaction specifically through composition ratios and morphology tailoring.…”