This report provides a method to estimate how much the photocurrents can be increased by adding gold nanoparticles in P3HT:PCBM films, without having to carry out the complex process of fabricate a whole cell. The tuning effect of varying the gold nanoparticle concentration on optical properties of these films was analyzed by measuring optical absorption. To estimate the contribution of the optical

The aim of this research was to describe a facile protocol to obtain biocompatible gold nanoparticles (AuNPs) suitable for microbial optical sensing. For this purpose, polycationic poly-L-lysine (PLL) was employed as both reducing and stabilizing agent in order to obtain an optically active microbial nanotag based on the electrostatic interaction with negatively charged cell envelopes. A one-pot procedure

This work investigates 2.5 – 30 nm gold nanoparticles immobilized on Al2O3. It shows that they possess high activity and stability in selective hydrogenation of phenylacetylene into styrene from a phenylacetylene-styrene mixture at 423 K. Strong dependences of the activity and selectivity of Au/ Al2O3 on the gold size were revealed: as the size of supported gold nanoparticles was decreased from 30

A common application of nanometer-sized gold particles is as seed particles for growth of semiconductor nanowires, which are believed to act as highly promising building blocks in future electronic devices. In a majority of the reports of successful nanowire growth, gold has been the seed particle material of choice. In this review article we identify the different types of gold particles used to initiate

The catalytic continuous gas phase hydrogenation of p-chloronitrobenzene (P=1 atm;T=423 K) has been investigated over a series of oxide (Al2O3, TiO2, Fe2O3 and CeO2) supported Au (1 mol %) catalysts. The application of two catalyst synthesis routes,i.e. impregnation (IMP) and deposition-precipitation (DP), has been considered where the DP route generated smaller mean Au particle sizes (1.5-2.8 nm)

This work was undertaken to investigate the effect of antigen-conjugated gold nanoparticles on the functional activity of cells of the reticuloendothelial system. Experiments using rat and mouse peritoneal cells assessed the dynamics of the total respiratory activity of macrophages and the activity of mitochondrial dehydrogenases on exposure to colloidal gold conjugates of high- and lowmolecular-weight

One-dimensional semiconductor nanowires are a promising candidate for future electronic devices. The epitaxial growth of nanowires is often mediated by metal seed particles, usually gold particles. In this paper the setup of a simple and robust technique to generate nanometer-sized aerosol gold particles by spark discharge is described. Furthermore we demonstrate for the first time that particles generated

A series of monolayer protected gold nanoparticle colloidal solutions have been prepared with average sizes in the 2–15nm range. If a drop of such a colloidal suspension is deposited onto a Si3N4 substrate and the solvent allowed to evaporate, the particles have a tendency to self-assemble into monolayer rafts with varying degrees of structural order depending on the initial mono-dispersity of the

The size effects of Au and ZrO2 particles on the structural property and the catalytic performance of Au/ZrO2 catalysts for the water gas shift reaction were extensively investigated. It was found that the Au-ZrO2 contact boundaries played essential roles in determining the catalytic reactivity. By keeping the size of Au particle to be ∼3 nm, the increase in the particle size of ZrO2 from ∼7 nm to

The aim of this work was to compare the microstructures of two high noble experimental Au-Pt alloys with similar composition with their corrosion and biocompatibility in vitro. We showed that Au-Pt II alloy, composed of 87.3 wt.% Au, 9.9 wt.% Pt, 1.7 wt.% Zn and 0.5 wt.% Ir + Rh + In, although possessing better mechanical properties than the Au-Pt I alloy (86.9 wt.% Au, 10.4 wt.% Pt, 1.5 wt.% Zn and

Gold nanoparticles in aqueous dispersion were prepared using the trisodium citrate reduction method to control the size of particles by changing the concentration of HAuCl4. The average particle size measured by DLS is higher than that obtained by TEM at a zeta potential of -40 mV. When trisodium citrate concentration is kept constant, the particle size increases with gold concentration. The kinetics

The analysis of FTIR absorption spectra of CO and of12CO-13CO isotopic mixtures is reported for gold catalysts supported on a number of oxides. Relationships between the nanostructure and the CO adsorbing properties of the different gold catalysts are discussed. In particular, on titania supported gold, where particles of metallic nature are present, two kinds of surface sites do adsorb CO, the 6-coordinated

Gold wires of different chemistry (denoted as Types A and B) are ballbonded on identical metallization and isothermally aged at 175°C. In both wire types the same intermetallic compounds Au4Al and Au8Al3 grow with parabolic time dependence as long as there is a supply of Al from the bondpad. After Al is completely reacted, composition of intermetallics in Type A wire remains unchanged but in Type B

The interfacial interaction of gold nanoparticles deposited on either model SiO2/Si(100) or high surface area amorphous or mesoporous silica with minute amounts of promoter oxide like “active” FeOx, TiO2 and CeO2 has been discussed. The role of the active oxide, its contribution to the perimeter along the gold nanoparticles has been interpreted. The oxide may invoke electronic interaction and simultaneously

Low temperature CH4 oxidation was studied on 2 nm gold nanoparticles supported on various metaloxides. The differences in reaction rates for the different systems suggest that the support material has an effect on the activity. From TEM analysis, we found that the gold particles were stable in size during the reaction. In addition to full oxidation to CO2, traces of C2H6 were detected when Au/TiO2

We describe an innovative approach based on alloying of metals to remove metal ions from drinking water. A novel adsorbent, gold nanoparticle supported on alumina, was developed for the removal of inorganic mercury from water. The observed adsorption capacity for mercury is 4.065 gm per gm of gold nanoparticles, which is ∼10 times higher metal adsorption capacity than previously reported adsorbents

Blue and purple gold alloys form in the alloying systems of gold with gallium/indium and aluminium respectively and are known to be very brittle and to possess low corrosion resistance. Taking into account these drawbacks this paper describes the results of a European funded research project. The properties of the blue and purple gold alloys and coatings such as corrosion resistance, metal release

A combination of two catalysts, Au/TiO2 and TS-1 were used to catalyze the demanding reaction of butene epoxidation in an aqueous solution using molecular oxygen under very mild reaction conditions. Peroxy initiator was not necessary but carbon monoxide as a sacrificial reductant was needed. Carbon monoxide conversions increase with time on stream suggesting the generation of a highly active aqueous

A simple method to prepare the rambutan-like hybrid nanospheres of Au-P123 is presented. The rambutan-like hybrid nanospheres of Au-P123 were characterized by transmission electron microscopy (TEM), Electron diffraction patterns and UV-vis absorption spectroscopy.

Stress corrosion cracking (SCC) is a well known form of environmental attack in low carat gold jewellery. It is desirable to have a quick, easy and cost effective way to detect SCC in alloys and prevent them from being used and later failing in their application. A facile chemical method to investigate SCC of 9 carat gold alloys is demonstrated. It involves a simple application of tensile stress to

Mechanisms proposed for the gold-catalysed Water-Gas Shift (WGS) are critically reviewed, and a complete reaction set and cycle involving activation of water on reduced support sites is considered; however, a modified route to CO2 formation by thermal decomposition of a carboxyl species results in a simpler and therefore more probable mechanism.

Gold clusters and nanoparticles were deposited on the three kinds of porous coordination polymers (PCP5), MOF-5, CPL-2, and AI-MIL53 by the solid grinding method. The size of Au particles depended on the kinds of PCPs and increased in the order of AI-MIL53 < CPL-2 < MOF-5. The mean diameter of Au particles supported on AI-MIL53 was estimated to be 1.6 nm by HAADFSTEM. Such small Au clusters on AI-MIL53

The liquid-phase oxidation of ethanol to acetic acid using Au catalysts supported on various metal oxides was studied at 150°C using molecular oxygen as stoichiometric oxidant. Catalysts containing 1 wt% Au supported on TiO2, Al2O3, and ZnO were examined for ethanol oxidation. The results showed that ZnO and TiO2 gave higher initial activities as supports for gold in ethanol oxidation, followed by

The ligand 1,1-bis[N,N′-(2-diphenylphosphino) amide]ferrocene, Fc(CONHCH2CH2PPh2)2 (L), has been synthesized by reaction of the chloro carbonyl derivative Fc(COCl)2 and the aminophosphine NH2CH2CH2PPh2. The coordination properties towards silver(I), gold(I) and gold(III) compounds have been explored. Several complexes with the diphosphine acting as bidentate chelating or bridgind ligand have been prepared

Much more work has been carried out on supported gold catalysts (also called “real” catalysts) than on gold single crystal surfaces. However, for fundamental understanding of catalysis by gold, well-defined gold surfaces and controlled conditions using the surface science approach may provide useful information concerning reaction mechanisms and the nature of active centers. This paper presents a brief

Despite Au, Al and Cu being individually very well-known elements, their ternary phase diagram has not been studied in as much detail as those of many other Au-containing ternaries. Here we review what is known, and consider the prospects for technological exploitation of some of the ternary compositions. The components of greatest interest in Al-Au-Cu may be the β-phases, at least two of which have

For more than a decade vinylgold(I) compounds were written as intermediates in gold-catalysed reactions of alkynes and allenes, but only now the experimental proof for their participation in catalytic cycles could be obtained. This includes preparative access to these species, which for the first time allows to expand this aspect of organogold chemistry in new directions.

Gold is active in various hydrogenation reactions and often shows exceptional high chemoselectivity when multiple functional groups are present. All hydrogenation reactions have in common, that the hydrogen molecules have to adsorb and dissociate before they react. Recent insights in the interaction of gold with hydrogen and simple reactions involving hydrogen are described.

The recent literature on simple gas-phase reactions involving CO, O2, H2, H2O and CO2 catalysed by gold is surveyed and mechanisms derived from the literature are presented and analysed. They provide a template by which further results can be assessed and additional necessary study stimulated. Ways in which the published results can be used to develop catalysts with the necessary activity and stability

This article is about the reaction of selective hydrogenation of 1,3-butadiene performed in an excess of alkenes (propene/butadiene ratio = 100) over supported gold catalysts, so as to mimic the conditions of purification of light alkenes (C4 cuts) from the presence of impurities (highly unsaturated compounds, 1–3%). Gold was found highly selective (close to 100%, no propane or butane formation) for

The effects of indium addition to CuAu on the alloy phase transformation behavior were investigated by hardness tests, electrical resistivity measurements, X-ray diffraction and transmission electron microscopy. These established that indium additions lower the critical temperature and stabilize the CuAu II phase at room temperature. Formation of the long period ordered phase produces an age-hardening;

In a study of the phenomenon of catalyst deactivation during storage, Au/TiO2 catalyst was stored under various conditions, viz. vacuum, nitrogen, air, refrigeration, dark, and light, and tested for CO oxidation activity at regular intervals. The data shows that the catalyst deactivates under all the storage conditions over 12 months and that storage in vacuum significantly enhances the rate and extent

High-resolution electron energy loss spectroscopy was used to investigate the electronic properties of (111)-oriented Au ultrathin films grown on Cu(111). The loss spectrum showed several features which were ascribed to both single and collective excitations. In particular we distinguished features assignable to dispersionless single-particle transitions and the dispersing electron-hole continuum as

CO is a useful probe in the characterization of surface properties of both metal and metal oxide via adsorption. Adsorption of CO was used to monitor the possible active site of an Au/TiO2 catalyst for the CO oxidation reaction. CO adsorption on the reduced catalyst results in the band at 2104 cm−1 indicative of Au0. During the reaction (in the presence of both CO and O2 present) the band is shifted

The gold(III) complex [Au(C6F5)2(SPNH2)]CIO4 (1) containing the S,N-donor ligand 2-(diphenylthiop hosphino)aniline (S=PNH2) can be easily prepared by treatment of S=PNH2 with [Au(C6F5)2(OEt2)2]CIO4 and deprotonated with PPN(acac) to afford [Au(C6F5)2(SPNH)] (2). Complex 2 can also be obtained in a one-step reaction from SPNH2 and [Au(C6F5)2(acac)]. The electronic density in excess in 2 can be employed

The electrocatalytic properties of nanostructured gold electrodes for glucose electro-oxidation in KOH were investigated by cyclic voltammetry and compared with a commercially available polycrystalline gold electrode. These electrodes were prepared by depositing gold nanoparticles from a sol onto different carbonaceous conductive supports: glassy carbon, carbon cloth and graphite paper. The gold sol

This study examined the age-hardening by miscibility limit in a multi-purpose dental gold alloy containing platinum. The hardness increased rapidly in the initial stage of the aging process, reached the maximum value, then decreased continuously with aging time. The significant hardness increase resulted from the heterogeneous precipitation of the Pt-rich β phase from the grain boundary of the Au-rich

Thin-gold films have been laid down on the inner surface of borosilicate capillaries using a variety of deposition techniques and the resultant film composition and morphology has been evaluated using energy-dispersive x-ray (EDX) and scanning electron microscopy (SEM) analysis, respectively. These films have been shown to couple very strongly with microwave irradiation to generate very high temperatures

Analysis of literature results for the effect of particle size in Au/TiO2 catalysts on their activities and activation energies (E) for CO oxidation by constructing ’Compensation’ plots of E vs. ln A (A = pre-exponential factor) leads directly to the conclusion that high activity is primarily due to particles so small as to be in the non-metallic state.

Thermosonic ball bonding is a major interconnect process in microelectronics packaging and is positioned to remain one of the key process technologies available to package designers in the near future. However, the main wire material used in fine pitch (FP) and ultra-fine pitch (UFP) ball bonding is gold and with significant increases in gold price, gold ball bonding has become a more costly process

This work presents an investigation into the Selective Laser Melting (SLM) of 24 carat gold (Au) powder with a mean particle size of 24μm. An SLM 100 system was used which is intended for production of highly detailed and intricate parts. Gold powder was tested for its properties such as tap density, Particle Size distribution (PSD) and reflectance etc. A suitable processing window was identified and

New possibilities in the design of gold-containing electrochemical coating systems for electronic applications are given by the incorporation of gold-nanoparticles in metal-matrix-systems. The major problem for the application of nanoparticles is the strong agglomeration of the particles in the electrolyte solutions, preventing the incorporation of nanoscaled dispersants.A complete new concept for

2 nm bimetallic alloyed Au-Pt nanoparticles were synthesized via electron beam irradiation. The nanoparticles were characterized using TEM and EDAX analysis, and tested as electrocatalysts for different fuel-cell related reactions. Our results show that these Au-Pt nanoparticles are promising for application in fuel cells.

In this paper we report the results of a deep investigation of gold title in jewellery alloys by means of potentiometric titration. After reviewing the suitable reactions for such purpose we focused on the most profitable one, which involves the use of hexadecylpyridinium chloride (CPC). This cation gives rise to selective and quantitative precipitation of AuCl4 −. We completely revised a method previously

The intense plasmon absorption bands of gold nanorods (GNRs) with peak extinction coefficients up to 6.4×109 M−1 cm−1 as well as their expected high stability make GNRs promising candidates for the colouration of bulk materials. The comparison of the integrated absorption in the visible region of GNRs with those of commercial organic pigments shows that the colouring strength of GNRs is 4 to 8 times

The unique properties of gold nanoparticles have stimulated the increasing interest in the application of GNPs in interfacing biological recognition events with signal transduction and in designing biosensing devices exhibiting novel functions. The optical properties of GNPs provide wide range opportunities for construction optical biosensors. The excellent biocompatibility, conductivity, catalytic

The attractive color of blue and especially purple gold alloys has always intrigued jewelry designers and producers. The reality of using these colors for jewelry has been very limited, however, mainly due to the inherent brittleness and poor corrosion resistance of this special class of gold alloys. The paper reports on some improvements in crack resistance that are obtained by particular additions

Molecular and nanoparticulate gold precursors for application in inkjet printing onto flexible substrates are discussed. The choice of stabilising ligands and the size of the nanoparticles influence the solution stability of the ink and their ability to form decorative or conductive functional films.

We report a simple and rapid process for the roomtemperature synthesis of gold nanoparticles using tannic acid, a green reagent, as both the reducing and stabilising agent. We systematically investigated the effect of pH on the size distribution of nanoparticles synthesized. Based on induction time and σ-potential measurements, we show that particle size distribution is controlled by a fine balance

High-resolution electron energy loss spectroscopy has been used to investigate the catalytic properties of Na-doped Au monolayer grown on Cu(111). The presence of Na atoms allows the dissociation of oxygen molecules and the stabilization of atomic oxygen. The strong reduction of the dissociation barrier for O2 promoted by Na could readily favor many surface chemical reactions, due to the key role of

CO is a useful probe in the characterization of surface properties of both metal and metal oxide via adsorption. Adsorption of CO was used to monitor the possible active site of an Au/TiO2 catalyst for the CO oxidation reaction. CO adsorption on the reduced catalyst results in the band at 2104 cm−1 indicative of Au0. During the reaction (in the presence of both CO and O2 present) the band is shifted

Recently, much progress has been made toward the fabrication of non-volatile memory devices based on metallic nanoparticles. Among the many kinds of nanoparticles, gold nanoparticles are some of the most widely used materials for charge trapping elements in non-volatile memory devices because they are chemically stable, easily synthesized, and have a high work function. Various synthesis methods have

Catalysts of highly dispersed gold supported on ceria were prepared by deposition precipitation method. Au is dispersed as Au0, Au+ and Au3+ species on ceria. The content of Au+ and Au3+ was highest on catalyst prepared on uncalcined ceria, which possess least ordered surface. It is inferred that oxygen vacancy on disordered ceria surface is essential for the preparation of highly dispersed gold catalysts

With over 300 tonnes of gold used in electronics each year, end-of-life electronic equipment offers an important recycling potential for the secondary supply of gold. With gold concentrations reaching 300-350 g/t for mobile phone handsets and 200-250 g/t for computer circuit boards, this “urban mine” is significantly richer than what is available in primary ores.However, the “mineralogy” in scrap products

The complex precipitation mechanisms related to the age-hardening of Cu-free Au-Ag-Pt-Zn-In alloy for multipurpose dental use was studied by means of hardness test, X-ray diffraction (XRD) studies, field emission scanning electron microscopic (FE-SEM) observations, energy dispersive spectrometer (EDS) analysis, and electron probe microanalysis (EPMA). The early diffusion and then clustering of the

The field of gold catalysis has been a lively area of research for the past two decades and gold catalysts are now an established ‘best choice’ for many oxidation reactions. Most well known for its performance in selective and preferential oxidation reactions, gold has more recently found potential in selective hydrogenation reactions. In this work the recent developments using gold and gold-promoted

Advanced hydrometallurgical separation processes are gaining significant importance for the recovery of gold from the aqueous solutions viz. leach liquor of waste electronics, plating material solutions, and waste wash water from electronic industries. In the present investigation, gold adsorption from the waste rinse water of semiconductor manufacturing industries is reported using Amberlite XAD-7HP

A facile, completely green, and cheap route for the synthesis of Au nanoparticles at 25–75° has been developed by using only hydrogen tetrachloroaurate as the precursor and gum arabic (GA) simultaneously as a reducing agent and a stabilizing agent. No extra reagents are needed. From the analyses of UV/VIS absorption spectra, TEM, HRTEM, SAED, and XRD patterns, the formation of Au nanoparticles with

Silver-poly (dimethylsiloxane) nanocomposite films are prepared by an in-situ synthesis by incubating the polymer film in a silver nitrate aqueous solution and using the reducing properties of the polymer’s curing agent. Silver nanoparticles concentrated in the surface layer of the silver-poly (dimethylsiloxane) nanocomposite are further replaced by gold through a galvanic replacement reaction at the

This work highlights new research into the fundamental properties of palladium-gold alloy membranes. Two types of self-supported palladium-gold foils were studied; membranes produced by magnetron sputtering and membranes produced by cold-working. The cold-worked membranes had thicknesses of 25 microns and gold contents from 0–40 wt% Au, while the sputtered films ranged from 10–31 microns in thickness