The two-step electrosynthesis of nanocomposites of Ag, Au, and Pd nanoparticles with iron(ii) oxide-hydroxide

The two-step electrosynthesis of metal nanoparticle (MNP, M = Ag, Pd, and Au) nanocomposites with iron oxide-hydroxide FeO-xFe(OH)2 was investigated.

Biogenic Synthesis of Silver Nanoparticles, Characterization and Their Applications—A Review

With the growing awareness for the need of sustainable environment, the importance of synthesizing and the application of green nanoparticles has gained special focus. Among various metal nanoparticles, silver nanoparticles (AgNPs) have gain significant attention. AgNPs are synthesized conventionally by physical and chemical methods using chemicals such as reducing agents, which are hazardous to environment due to their toxic properties, provoking a serious concern to create and develop environment friendly methods. Thus, biological alternatives are emerging to fill gaps, such as green syntheses that use biological molecules taken from plant sources in the form of extracts, which have shown to be superior to chemical and physical approaches. These biological molecules derived from plants are assembled in a highly regulated manner to make them suitable for metal nanoparticle synthesis. The current review outlines the wide plant diversity that may be used to prepare a rapid and single-step procedure with a green path over the traditional ones, as well as their antifungal activity.

Damage Analysis in Ag Nanoparticle Interconnect Line Under High-Density Electric Current

Printed electronics (PEs) have attracted attention for the fabrication of microscale electronic circuits. PEs use conductive inks which include metal nanoparticles. The conductive ink can be printed on flexible substrates for wearable devices using ink-jet printers and roll-to-roll methods. With the scaling down of electric devices, the current density and Joule heating in the device lines increase, and electromigration (EM) damage becomes significant. EM is a transportation phenomenon of metallic atoms caused by the electron wind under high-density current. Reducing the EM damage is extremely important to enhance the device reliability. With the progress in miniaturization of the metal nanoparticle ink lines, EM problem needs to be solved for ensuring the reliability of these lines. We know that the formation of aggregates and cathode damages occur due to a current loading. The diffusion path of atoms due to the EM has not been identified under the high-density current loading. In this study, a high-density electric current loading was applied to an Ag nanoparticle line. The line specimens were prepared using a lift-off method. After the current loading tests, observations were conducted using a laser microscope and scanning electron microscope. A local decrease in the line thickness and scale-shaped slit-like voids were observed due to the high-density current loading. Moreover, the microstructure of the line was modified by enlarging the Ag grain. From the results, we identified that a dominant diffusion occurred at the Ag grain boundary due to the EM.

Swift Reduction of Nitroaromatics By Gold Nanoparticles Anchored On Steam-Activated Carbon Black Via Simple Preparation

Gold (Au) nanoparticles supported on certain platforms display highly efficient activity on nitroaromatics reduction. In this study, steam-activated carbon black (SCB) was used as a platform to fabricate Au/SCB catalysts via a green and simple method for 4-nitrophenol (4-NP) reduction. The obtained Au/SCB catalysts exhibit efficient catalytic performance in reduction of 4-NP (rate constant kapp = 2.1925 min-1). The effects of SCB activated under different steam temperature, Au loading amount, pH and reaction temperature were studied. The structural advantages of SCB as a platform were analyzed by various characterizations. Especially, the result of N2 adsorption-desorption method showed that steam activating process could bring higher surface area (from 185.9689 m²/g to 249.0053 m²/g), larger pore volume (from 0.073268 cm³/g to 0.165246 cm³/g) and more micropore for SCB when compared with initial CB, demonstrating the suitable of SCB for Au NPs anchoring, thus promoting the catalytic activity. This work contributes to the fabrication of other supported metal nanoparticle catalysts for preparing different functional nanocomposites for different applications.

Optical soliton in a one-dimensional array of a metal nanoparticle-microcavity complex (2021 Commun. Theor. Phys. 73 115105)

During the production process an error was introduced into equation (14). The absolute value symbol was moved to the wrong place. Here, we give the correct version of equation (14) ：

Controlling the Pump-Probe Optical Response in Asymmetric Tunneling-Controlled Double Quantum Dot Molecule—Metal Nanoparticle Hybrids

In the present work, we investigate the modified nonlinear pump-probe optical properties due to the excitonic–plasmonic interaction of a double semiconductor quantum dot (SQD) molecule coupled to a metal nanoparticle (MNP). More specifically, we study the absorption and the dispersion spectra of a weak electromagnetic field in a hybrid structure with two counterparts, a molecule of two coupled SQDs, and a spherical MNP driven by a field of high intensity. We solve the relevant density matrix equations, calculate the first-order optical susceptibility of the probe field in the strong pumping regime, and investigate the way in which the distance between the two counterparts modifies the optical response, for a variety of values of the physical constants of the system, including the pump-field detuning, the tunnelling rate, and the energy separation gap associated with the excited states of the coupled SQDs.

Optimisation and Scale-up of the Synthesis of Gold Nanoparticle-Wool Fibre Composites

<p>Gold nanoparticles are known for their remarkable optical properties; they exhibit localised surface plasmon resonance bands in the visible region of the electromagnetic spectrum. This has led to their use as luxury dyes for the colouring of wool fibres. Gold is associated with wealth and desire, and as such, gold nanoparticle-wool fibre composites may be fabricated into high-quality garments, apparel, textiles and carpets for international markets. Novel proprietary approaches for the laboratory-scale synthesis of gold nanoparticle-wool fibre composites have previously been developed by Professor James Johnston and Dr Kerstin Lucas. The innovative nanotechnology utilises the affinity of gold for sulfur-containing cystine residues in wool fibres, to attract and bind the gold nanoparticles. One approach involves the absorption of gold ions by wool fibres and the nucleation of gold nanoparticles in-situ. In an alternative method, gold nanoparticle colloids are synthesised ex-situ, and are then used to colour wool fibres. The reaction conditions of the in-situ and ex-situ approaches were optimised with respect to cost-effectiveness and scalability. The gold content of the in-situ composites was minimised, and the range of possible colours widened, via the use of heat and external reducing agents. In the ex-situ process, the formation and stability of the gold nanoparticle colloids was studied, and the reaction conditions of the synthesis were optimised. The rate of uptake of gold nanoparticles to wool was controlled by manipulating the pH, concentration, volume, and wool to liquor ratio of the gold colloids, and by introducing auxiliary agents into the dyeing reactions. A range of chemical treatments and alternative stabilising agents were investigated to improve the washfastness properties of ex-situ gold nanoparticle-wool fibre composites. There are numerous size-controllable syntheses of gold nanoparticle colloids at the laboratory-scale. However, when the process is scaled-up, gold nanoparticle synthesis is no longer trivial. A barrel reactor with a high velocity mixer was utilised to achieve uniform mixing and heating in the synthesis of gold nanoparticle colloids of up to 90 L in volume. The ratios of gold to stabilising agents in the colloidal gold syntheses were optimised to result in more stable and reproducible gold colloids for subsequent dyeing reactions. The uniform colouring of small quantities of wool is easily achieved in the laboratory, but preventing colour variation across a kilogram of wool is a significant challenge. Initial kilogram-scale dyeing reactions in static tank reactors resulted in unevenly coloured gold nanoparticle-wool fibre composites. To overcome this, conventional hank dyeing equipment was used to colour felted merino yarn, in collaboration with the wool dyeing industry. Modified hank dyeing procedures were recreated in the laboratory, and composites with remarkable colour uniformity were produced. Industrial package dyeing reactors were then used to colour fine merino yarn with gold nanoparticle colloids. The uptake of gold nanoparticles was controlled by manipulating the owrates, ow direction and amounts of auxiliary agents that were employed in the dyeing reactions. Based upon the success of the industrial dyeing reactions, novel dyeing reactors were developed for the colouring of hanks of wool fibres and yarns in the laboratory. These reactors utilised rapid dye circulation and pressure to produce gold nanoparticle-wool fibre composites with remarkable colour uniformity. The composites were used to fabricate luxury apparel and carpets for international trade expositions. The pathway from synthesis in the laboratory to pilot-scale production of gold nanoparticle-wool fibre composites is presented. The PhD research was an integral step in the successful commercialisation of this innovative nanotechnology, and will assist in scaling-up the synthesis of metal nanoparticle colloids and nanocomposites in the future.</p>

Optimisation and Scale-up of the Synthesis of Gold Nanoparticle-Wool Fibre Composites

<p>Gold nanoparticles are known for their remarkable optical properties; they exhibit localised surface plasmon resonance bands in the visible region of the electromagnetic spectrum. This has led to their use as luxury dyes for the colouring of wool fibres. Gold is associated with wealth and desire, and as such, gold nanoparticle-wool fibre composites may be fabricated into high-quality garments, apparel, textiles and carpets for international markets. Novel proprietary approaches for the laboratory-scale synthesis of gold nanoparticle-wool fibre composites have previously been developed by Professor James Johnston and Dr Kerstin Lucas. The innovative nanotechnology utilises the affinity of gold for sulfur-containing cystine residues in wool fibres, to attract and bind the gold nanoparticles. One approach involves the absorption of gold ions by wool fibres and the nucleation of gold nanoparticles in-situ. In an alternative method, gold nanoparticle colloids are synthesised ex-situ, and are then used to colour wool fibres. The reaction conditions of the in-situ and ex-situ approaches were optimised with respect to cost-effectiveness and scalability. The gold content of the in-situ composites was minimised, and the range of possible colours widened, via the use of heat and external reducing agents. In the ex-situ process, the formation and stability of the gold nanoparticle colloids was studied, and the reaction conditions of the synthesis were optimised. The rate of uptake of gold nanoparticles to wool was controlled by manipulating the pH, concentration, volume, and wool to liquor ratio of the gold colloids, and by introducing auxiliary agents into the dyeing reactions. A range of chemical treatments and alternative stabilising agents were investigated to improve the washfastness properties of ex-situ gold nanoparticle-wool fibre composites. There are numerous size-controllable syntheses of gold nanoparticle colloids at the laboratory-scale. However, when the process is scaled-up, gold nanoparticle synthesis is no longer trivial. A barrel reactor with a high velocity mixer was utilised to achieve uniform mixing and heating in the synthesis of gold nanoparticle colloids of up to 90 L in volume. The ratios of gold to stabilising agents in the colloidal gold syntheses were optimised to result in more stable and reproducible gold colloids for subsequent dyeing reactions. The uniform colouring of small quantities of wool is easily achieved in the laboratory, but preventing colour variation across a kilogram of wool is a significant challenge. Initial kilogram-scale dyeing reactions in static tank reactors resulted in unevenly coloured gold nanoparticle-wool fibre composites. To overcome this, conventional hank dyeing equipment was used to colour felted merino yarn, in collaboration with the wool dyeing industry. Modified hank dyeing procedures were recreated in the laboratory, and composites with remarkable colour uniformity were produced. Industrial package dyeing reactors were then used to colour fine merino yarn with gold nanoparticle colloids. The uptake of gold nanoparticles was controlled by manipulating the owrates, ow direction and amounts of auxiliary agents that were employed in the dyeing reactions. Based upon the success of the industrial dyeing reactions, novel dyeing reactors were developed for the colouring of hanks of wool fibres and yarns in the laboratory. These reactors utilised rapid dye circulation and pressure to produce gold nanoparticle-wool fibre composites with remarkable colour uniformity. The composites were used to fabricate luxury apparel and carpets for international trade expositions. The pathway from synthesis in the laboratory to pilot-scale production of gold nanoparticle-wool fibre composites is presented. The PhD research was an integral step in the successful commercialisation of this innovative nanotechnology, and will assist in scaling-up the synthesis of metal nanoparticle colloids and nanocomposites in the future.</p>