Surface plasmons in quantum-sized noble-metal clusters: TDDFT quantum calculations and the classical picture of charge oscillations

2015 ◽  
Vol 17 (42) ◽  
pp. 28379-28386 ◽  
Author(s):  
Hans-Christian Weissker ◽  
Xóchitl López-Lozano
Keyword(s):  
Surface Plasmons ◽  
Noble Metal ◽  
Noble Metals ◽  
Metal Clusters ◽  
Quantum Calculations ◽  
Electronic Density ◽  
Charge Oscillation ◽  
Classical Picture

The dynamics of the electronic density corresponds to a collective charge oscillation, albeit influenced by the inhomogeneity of noble metals.

scholarly journals How metallic are noble-metal clusters? Static screening and polarizability in quantum-sized silver and gold nanoparticles

Nanoscale ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 4452-4458 ◽  
Author(s):  
Rajarshi Sinha-Roy ◽  
Pablo García-González ◽  
Hans-Christian Weissker
Keyword(s):  
Gold Nanoparticles ◽  
Noble Metal ◽  
Metal Clusters ◽  
External Fields ◽  
Atomic Shell ◽  
Silver And Gold Nanoparticles ◽  
Electronic Shell ◽  
Friedel Oscillations ◽  
Static Screening ◽  
Classical Picture

Small noble-metal clusters of about 2 nm are strongly metallic, even one atomic shell screens 96% of external fields, whereas electronic shell-closings and Friedel oscillations modify the classical picture.

Adsorption of the Gas Molecules (NH3, C2H6O, C3H6O, CO, H2S) on noble metal (Ag, Au, Pt, Pd, Ru)–Doped MoSe2 Monolayer: A First-Principles Study

2021 ◽  
Author(s):  
Lanjuan Zhou ◽  
Sujing Yu ◽  
Yan Yang ◽  
Qi Li ◽  
Tingting Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Noble Metal ◽  
First Principles ◽  
Density Functional ◽  
Noble Metals ◽  
Gas Sensing ◽  
Functional Theory ◽  
First Principles Study ◽  
Gas Molecules ◽  
Sensing Performance

In this paper, the effects of five noble metals (Au, Pt, Pd, Ag, Ru) doped MoSe2 on improving gas sensing performance were predicted through density functional theory (DFT) based on...

scholarly journals Luminescent Supramolecular Nano- or Microstructures Formed in Aqueous Media by Amphiphile-Noble Metal Complexes

2020 ◽  
Vol 2020 ◽  
pp. 1-24 ◽  
Author(s):  
Carmen Cretu ◽  
Loredana Maiuolo ◽  
Domenico Lombardo ◽  
Elisabeta I. Szerb ◽  
Pietro Calandra
Keyword(s):  
Noble Metal ◽  
Smart Materials ◽  
Self Assembly ◽  
Noble Metals ◽  
Photophysical Properties ◽  
Aqueous Media ◽  
Molecular Architecture ◽  
Stimuli Responsive ◽  
Panoramic View ◽  
Amphiphilic Molecules

The involvement of metal ions within the self-assembly spontaneously occurring in surfactant-based systems gives additional and interesting features. The electronic states of the metal, together with the bonds that can be established with the organic amphiphilic counterpart, are the factors triggering new photophysical properties. Moreover, the availability of stimuli-responsive supramolecular amphiphile assemblies, able to disassemble in a back-process, provides reversible switching particularly useful in novel approaches and applications giving rise to truly smart materials. In particular, small amphiphiles with an inner distribution, within their molecular architecture, of various polar and apolar functional groups, can give a wide variety of interactions and therefore enriched self-assemblies. If it is joined with the opportune presence and localization of noble metals, whose chemical and photophysical properties are undiscussed, then very interesting materials can be obtained. In this minireview, the basic concepts on self-assembly of small amphiphilic molecules with noble metals are shown with particular reference to the photophysical properties aiming at furnishing to the reader a panoramic view of these exciting problematics. In this respect, the following will be shown: (i) the principles of self-assembly of amphiphiles that involve noble metals, (ii) examples of amphiphiles and amphiphile-noble metal systems as representatives of systems with enhanced photophysical properties, and (iii) final comments and perspectives with some examples of modern applications.

scholarly journals Current Strategies for Noble Metal Nanoparticle Synthesis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Giyaullah Habibullah ◽  
Jitka Viktorova ◽  
Tomas Ruml
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Drug Carriers ◽  
Industrial Applications ◽  
Metal Nanoparticle ◽  
Noble Metal Nanoparticles ◽  
Synthesis Methods ◽  
Gold And Silver Nanoparticles ◽  
Diverse Range ◽  
The Past

AbstractNoble metals have played an integral part in human history for centuries; however, their integration with recent advances in nanotechnology and material sciences have provided new research opportunities in both academia and industry, which has resulted in a new array of advanced applications, including medical ones. Noble metal nanoparticles (NMNPs) have been of great importance in the field of biomedicine over the past few decades due to their importance in personalized healthcare and diagnostics. In particular, platinum, gold and silver nanoparticles have achieved the most dominant spot in the list, thanks to a very diverse range of industrial applications, including biomedical ones such as antimicrobial and antiviral agents, diagnostics, drug carriers and imaging probes. In particular, their superior resistance to extreme conditions of corrosion and oxidation is highly appreciated. Notably, in the past two decades there has been a tremendous advancement in the development of new strategies of more cost-effective and robust NMNP synthesis methods that provide materials with highly tunable physicochemical, optical and thermal properties, and biochemical functionalities. As a result, new advanced hybrid NMNPs with polymer, graphene, carbon nanotubes, quantum dots and core–shell systems have been developed with even more enhanced physicochemical characteristics that has led to exceptional diagnostic and therapeutic applications. In this review, we aim to summarize current advances in the synthesis of NMNPs (Au, Ag and Pt).

scholarly journals Rhodium Oxide Surface-Loaded Gas Sensors

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 892 ◽  
Author(s):  
Anna Staerz ◽  
Inci Boehme ◽  
David Degler ◽  
Mounib Bahri ◽  
Dmitry Doronkin ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Noble Metal ◽  
Noble Metals ◽  
Metal Cluster ◽  
Empirical Work ◽  
Oxide Surface ◽  
Metallic State ◽  
X Ray ◽  
Rhodium Clusters ◽  
Sensing Characteristics

In order to increase their stability and tune-sensing characteristics, metal oxides are often surface-loaded with noble metals. Although a great deal of empirical work shows that surface-loading with noble metals drastically changes sensing characteristics, little information exists on the mechanism. Here, a systematic study of sensors based on rhodium-loaded WO3, SnO2, and In2O3—examined using X-ray diffraction, high-resolution scanning transmission electron microscopy, direct current (DC) resistance measurements, operando diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and operando X-ray absorption spectroscopy—is presented. Under normal sensing conditions, the rhodium clusters were oxidized. Significant evidence is provided that, in this case, the sensing is dominated by a Fermi-level pinning mechanism, i.e., the reaction with the target gas takes place on the noble-metal cluster, changing its oxidation state. As a result, the heterojunction between the oxidized rhodium clusters and the base metal oxide was altered and a change in the resistance was detected. Through measurements done in low-oxygen background, it was possible to induce a mechanism switch by reducing the clusters to their metallic state. At this point, there was a significant drop in the overall resistance, and the reaction between the target gas and the base material was again visible. For decades, noble metal loading was used to change the characteristics of metal-oxide-based sensors. The study presented here is an attempt to clarify the mechanism responsible for the change. Generalities are shown between the sensing mechanisms of different supporting materials loaded with rhodium, and sample-specific aspects that must be considered are identified.

scholarly journals Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

2018 ◽  
Vol 9 ◽  
pp. 2763-2774 ◽  
Author(s):  
Alexander Rostek ◽  
Marina Breisch ◽  
Kevin Pappert ◽  
Kateryna Loza ◽  
Marc Heggen ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Noble Metals ◽  
Biological Effects ◽  
Human Mesenchymal Stem Cells ◽  
Average Diameter ◽  
Vinyl Pyrrolidone ◽  
Noble Metal Nanoparticles ◽  
Spherical Average ◽  
Size And Morphology

For a comparative cytotoxicity study, nanoparticles of the noble metals Rh, Pd, Ag, Pt, and Au (spherical, average diameter 4 to 8 nm) were prepared by reduction in water and colloidally stabilized with poly(N-vinyl pyrrolidone) (PVP). Thus, their shape, size, and surface functionalization were all the same. Size and morphology of the nanoparticles were determined by dynamic light scattering (DLS), analytical disc centrifugation (differential centrifugal sedimentation, DCS), and high-resolution transmission electron microscopy (HRTEM). Cell-biological experiments were performed to determine the effect of particle exposure on the viability of human mesenchymal stem cells (hMSCs). Except for silver, no adverse effect of any of the metal nanoparticles was observed for concentrations up to 50 ppm (50 mg L−1) incubated for 24 h, indicating that noble metal nanoparticles (rhodium, palladium, platinum, gold) that do not release ions are not cytotoxic under these conditions.

scholarly journals Specific-Ion Effects Directed Noble Metal Aerogels: Versatile Manipulation for Electrocatalysis and Beyond

2019 ◽  
Author(s):  
RAN DU ◽  
YUE HU ◽  
René Hübner ◽  
Jan-Ole Joswig ◽  
Xuelin Fan ◽  
...  
Keyword(s):  
Porous Materials ◽  
Noble Metal ◽  
Noble Metals ◽  
Sol Gel ◽  
Synthetic Methods ◽  
Superior Performance ◽  
Gelation Mechanism ◽  
Practical Applications ◽  
Specific Ion Effects ◽  
Ion Effects

<div>Noble metal foams (NMFs) are a new class of functional porous materials featuring properties of both noble metals and monolithic porous materials, providing impressive prospects in catalysis, bio-sensing, plasmonic technologies, etc...Among reported synthetic methods to date, the sol-gel approach manifests overwhelming advantages for versatile synthesis of controlled nanostructured NMFs under mild condition. However, limited gelation methods and insufficient understanding of the underlying mechanism retards structure/composition manipulation of NMFs, hampering ondemand designing for practical applications. Herein highly tunable NMFs are fabricated at room temperature by activating specific-ion effects and regulating ion-nanoparticle interactions, affording various single/alloy NMFs with adjustable compositions (Au, Ag, Pd, Pt), ligament sizes (3.1~142.0 nm), and special morphologies. Their superior performance in programmable self-propulsion devices and electrocatalytic alcohol oxidation are demonstrated. This study provides not only a conceptually new route to fabricate and manipulate functional NMFs, but also an overall picture in understanding the gelation mechanism. It may pave the way for on-target designing versatile NMFs for various applications.</div>

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