Silver Nano/Microparticles: Modification and Applications 2.0

Nano Silver-Induced Toxicity and Associated Mechanisms

Nano silver is one of the most widely used engineering nanomaterials with antimicrobial activity against bacteria, fungi, and viruses. However, the widespread application of nano silver preparations in daily life raises concerns about public health. Although several review articles have described the toxicity of nano silver to specific major organs, an updated comprehensive review that clearly and systematically outlines the harmful effects of nano silver is lacking. This review begins with the routes of exposure to nano silver and its distribution in vivo. The toxic reactions are then discussed on three levels, from the organ to the cellular and subcellular levels. This review also provides new insights on adjusting the toxicity of nano silver by changing their size and surface functionalization and their combination with other materials to form a composite formulation. Finally, future development, challenges, and research directions are discussed.

Gold nanobipyramids doped with Au/Pd alloyed nanoclusters for high efficiency ethanol electrooxidation

Plasmonic metal nanostructures are of great interest due to their excellent physicochemical properties and promising applications in a wide range of technical fields. Among metal nanostructures, bimetallic nanostructures with desired morphologies, such as core-shell, uniform alloy and surface decoration, are of great interest due to their improved properties and superior synergetic effects. In this paper, Au/Pd nanoclusters were deposited on the surface of gold nanobipyramids (AuBPs) into a core-shell nanostructure (AuBP@Au _x Pd_1-x ) through a reductive co-precipitation method. The AuBP@Au _x Pd_1-x nanostructure integrates effectively the advantages of plasmonic AuBPs and catalytic Pd ultrafine nanoclusters, as well as the stable Au/Pd alloy shell. The AuBP@Au _x Pd_1-x nanostructure exhibits superior electrocatalytic activity and durability for oxygen reduction in alkaline media owing to the synergistic effect between the AuBP core and Au/Pd shell. Furthermore, the shell thickness of AuBP@Au _x Pd_1-x nanostructures can be adjusted by varying the amount of precursor. Overall, the catalytic activity of bimetallic Au/Pd catalysts is likely to be governed by a complex interplay of contributions from the particle size and shape.

Fabrication of Ag micro-particles based on stress-induced migration by using multilayered structure with artificial holes array

Silver micro/nanomaterials have attracted a great deal of attention due to their superior physicochemical properties. The atomic migration driven by electromigration or stress-induced migration has been demonstrated to be a promising method for the fabrication of metallic micro-/nanomaterials because of the advantage of simple processing. However, how to realize the controllable fabrication and mass production is still the critical technical problem for the method to be used in large-scale industrial applications. In this paper, the multilayered samples consisted of copper foil substrate, Ti adhesive layer, Ag film, and TiN passivation layer and with arrays of artificial holes on the passivation layer were applied to prepare arrays of Ag micro-particles. For the purpose of controllable fabrication, stress-induced migration experiments combined with finite element simulation were applied to analyze the influence of the passivation layer thickness and the heating temperature on the atom migration and Ag particles growing behavior. And the relationship between size of the fabricated Ag particles and the processing parameters of stress-induced migration experiments were also investigated. As a result, a proper structure size of the multilayered samples and heating temperature were recommended, which can be used for the Ag micro-particles controllable fabrication and mass production.