Fabrication of fully covered Cu–Ag core–shell nanoparticles by compound method and anti-oxidation performance

Abstract

Cu–Ag core–shell nanoparticles with a size of 8 nm were synthesized by the compound method of replacement reaction and chemical reduction reaction. A fully covered Cu–Ag core–shell structure was obtained by controlling the two different silver sources and electroless silver plating time. The optimum condition uses silver ammonia reacted for 14 h. The process of electroless silver plating uses the mixed growth model of layered growth and island growth. Silver atoms firstly attach to the surface of the as-prepared copper nanoparticles to form the dotted Ag atom structure by galvanic displacement reaction between Cu and [Ag(NH3)2]+, and then more silver atoms, reduced by sodium citrate, gradually deposit on the copper surface to form a fully covered structure. The morphology and core–shell structure of the nanoparticles was observed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The simultaneous thermal analyzer results confirmed that the weight gain of Cu–Ag core–shell nanoparticles was 2.2% when heated up to 400 °C, which was lower than pure Cu nanoparticles. According to the x-ray photoelectron spectroscopy results, the Cu–Ag core–shell nanoparticles exhibited good anti-oxidation performance compared with the pure copper nanoparticles after being stored for one month under the ambient conditions.

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

“…Lattice mismatch in larger nanostructures such as Cu/Ag nanowires , changes the thickness of the resulting Ag shell layer both due to system scale and strain effects. Precise synthetic control is difficult to achieve over multiple scales with GRR method, and related work ,, shows that Ag shell thicknesses can be varied through external deposition techniques over different NC sizes. The high level of consistency between the model and the experimental results here is attributed to the relatively small size and great uniformity of the NCs used as well as to the slow GRR reaction rate under mild conditions.…”

Self-Organizing, Environmentally Stable, and Low-Cost Copper–Nickel Complex Inks for Printed Flexible Electronics

“…As a result, during a single annealing process of the Cu−Ni complex inks, Cu@Ni core−shell structures are generated in situ by the above self-organized process and sintered to form highly reliable Cu−Ni alloy patterns for use in electronic devices. Compared with previous investigations in which Cu@Ni(Ag) core−shell particle inks were synthesized in advance and then subjected to a high-temperature sintering process to form Cu−Ni(Ag) alloy patterns, 32,33,35,36 our developed Cu−Ni complex inks with a self-organizing ability is simple, environmentally friendly, and more compatible with mass production methods, which is necessary for the costeffective manufacturing of PE products.…”

Catalytic Membrane Nanoreactor with Cu–Agx Bimetallic Nanoparticles Immobilized in Membrane Pores for Enhanced Catalytic Performance

“…Heterostructured nanomaterials have gained increased attention because they display multiple functionalities, selectivity, superior catalytic activity, and stability compared to monometallic nanomaterials, also the respective characteristics can be retained. − The catalytic performance of any hetero-nanostructure is highly dependent on several factors, such as compositions, sizes, and shapes. − Among a number of architectures, a core–shell structure formed by supporting metal nanoparticles as islands on the core of another metal substrate stands out due to a series of benefits. − First, the loss of core activity derived from the agglomeration of the shell metal can be dramatically suppressed . Second, the catalytic activity can be guaranteed due to the small size and large specific area of the spatially separated shell metal islands. , In terms of the fabricating methods, the galvanic replacement reaction based on the potential difference is a simple method for fabricating a core–shell structure with metal islands supported on another core metal. − Basically, this method was used to deposit more noble metals with higher reduction potentials on non-noble metals with relatively lower reduction potentials so that several benefits can be achieved. First, the overall cost of catalysts can be reduced because most of the expensive noble metal particles cores can be replaced by inexpensive ones.…”

“…Second, the reaction process is spontaneous without any extra energies (thermal energy, electricity, etc.). Moreover, several researchers had pointed out that the galvanic replacement reaction can easily be controlled by adjusting the reaction time, reaction temperature, and ion concentration to achieve a specific structure with outstanding performance. ,− …”