Synthesis of Au or Pt@Perovskite Nanocrystals via Interfacial Photoreduction

The surface modification of perovskite nanocrystals (NCs) (i.e., their decoration with noble metals) holds great promise with respect to the tailoring of their properties but has remained a challenge because perovskite NCs are extremely sensitive to water and alcohols. In this study, Au or Pt@CsPbBr3 NCs were successfully synthesized by photoreduction at the water/hexane interface. First, Cs4PbBr6 NCs were synthesized through the hot-injection method. Then, Cs4PbBr6 was transformed into CsPbBr3 and subjected to noble metal modification, both at the interface. The synthesized CsPbBr3 NCs exhibited a cubic perovskite phase and had an average size of approximately 13.5 nm. The deposited Au and Pt nanoparticles were crystalline, with a face-centered cubic lattice and average diameters of approximately 3.9 and 4.4 nm, respectively. The noble metal modification process had almost no effect on the steady-state photoluminescence (PL) emission wavelength but affected the charge-recombination kinetics of the CsPbBr3 NCs. Time-resolved PL decay spectral analysis indicated that the fluorescence lifetimes of the Au and Pt@CsPbBr3 NCs were shorter than those of the pure CsPbBr3 NCs, probably owing to the quenching of the free charges because of electron transfer from the perovskite to the noble metal nanoparticles.

Download Full-text

The Influence of the Ratio of Au and Pt Nanoparticles in Ternary Composites with TiO2

Metals ◽

10.3390/met11040628 ◽

2021 ◽

Vol 11 (4) ◽

pp. 628

Author(s):

Boglárka Hampel ◽

Lucian Baia ◽

Klara Hernadi ◽

Zsolt Pap

Keyword(s):

Oxalic Acid ◽

Metal Nanoparticles ◽

Noble Metal ◽

Noble Metals ◽

Diffuse Reflectance Spectroscopy ◽

Uv Light ◽

Production Capacity ◽

Pt Nanoparticles ◽

Noble Metal Nanoparticles ◽

Sacrificial Agent

In the present work, ternary composites were synthesized from commercial titanias (Evonik Aeroxide P25, Aldrich anatase—AA and Aldrich rutile—AR) and two noble metals (gold and platinum). This research focuses on the composition of the photocatalysts, especially on the noble metals. The ratio between the noble metals varies from 0.25 to 0.75% in each composite for each noble metal. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS) measurements were carried out to investigate the structural and optical properties. From the TEM, it can be observed that the particle sizes of the noble metals were between 1 and 4 nm, while the (anatase and rutile) crystals of P25 were 20–40 nm. The XRD showed that the semiconductors’ composition remained unchanged during/after the deposition of noble metal nanoparticles. By the DRS measurements, using the Kubelka–Munk equation, it can be concluded that the deposition of the noble metal nanoparticles resulted the decrease of the bandgap energies of the titanias. The photocatalytic activity was investigated under the irradiation of UV light. Oxalic acid and salicylic acid were used as model pollutants. The hydrogen production capacity was investigated as well, where the sacrificial agent was oxalic acid, and UV irradiation was used.

Download Full-text

Current Strategies for Noble Metal Nanoparticle Synthesis

Nanoscale Research Letters ◽

10.1186/s11671-021-03480-8 ◽

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).

Download Full-text

Exterior and Internal Uniform Loading of Pt Nanoparticles on Yolk-Shell La2O3 by Acoustic Levitation Synthesis with Enhanced Photocatalytic Performance

Materials ◽

10.3390/ma13010107 ◽

2019 ◽

Vol 13 (1) ◽

pp. 107 ◽

Cited By ~ 1

Author(s):

Ming Qin ◽

Qing Chang ◽

Yinkai Yu ◽

Hongjing Wu

Keyword(s):

Metal Oxide ◽

Metal Nanoparticles ◽

Noble Metal ◽

Shell Structure ◽

Photocatalytic Performance ◽

Chemical Interaction ◽

Pt Nanoparticles ◽

Noble Metal Nanoparticles ◽

Homogeneous Distribution ◽

Acoustic Levitation

By the deposition of noble metal nanoparticles on a metal oxide substrate with a specific micro-/nanostructure, namely, yolk-shell structure, a remarkable improvement in photocatalytic performance can be achieved by the composites. Nevertheless, noble metal nanoparticles only distribute on the surface shell of metal oxide substrates when the conventional wet-chemistry reduction approach is employed. Herein, we proposed a novel acoustic levitation synthesis of Pt nanoparticles deposited on yolk-shell La2O3. The composites not only displayed well-defined, homogeneous distribution of Pt NPs on the exterior shell of La2O3 and the interior La2O3 core, but an enhanced chemical interaction between Pt and La2O3. The unique structure not only can display improved photocatalytic degradation rate toward methyl orange, but also may show great potential in fields of hydrogen generation, environmental protection, etc. The novel acoustic levitation synthesis can supplement the methodology of synthesizing well dispersed noble metal oxides over the whole yolk-shell structure through noble metal NPs deposition method.

Download Full-text

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

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.9.258 ◽

2018 ◽

Vol 9 ◽

pp. 2763-2774 ◽

Cited By ~ 9

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.

Download Full-text

Noble Metal Composite Porous Silk Fibroin Aerogel Fibers

Materials ◽

10.3390/ma12060894 ◽

2019 ◽

Vol 12 (6) ◽

pp. 894 ◽

Cited By ~ 4

Author(s):

Alexander Mitropoulos ◽

F. Burpo ◽

Chi Nguyen ◽

Enoch Nagelli ◽

Madeline Ryu ◽

...

Keyword(s):

Noble Metal ◽

Silk Fibroin ◽

Noble Metals ◽

Metal Salt ◽

Supercritical Drying ◽

Noble Metal Nanoparticles ◽

Metal Composite ◽

Composite Aerogel ◽

Wide Range ◽

Composite Aerogels

Nobel metal composite aerogel fibers made from flexible and porous biopolymers offer a wide range of applications, such as in catalysis and sensing, by functionalizing the nanostructure. However, producing these composite aerogels in a defined shape is challenging for many protein-based biopolymers, especially ones that are not fibrous proteins. Here, we present the synthesis of silk fibroin composite aerogel fibers up to 2 cm in length and a diameter of ~300 μm decorated with noble metal nanoparticles. Lyophilized silk fibroin dissolved in hexafluoro-2-propanol (HFIP) was cast in silicon tubes and physically crosslinked with ethanol to produce porous silk gels. Composite silk aerogel fibers with noble metals were created by equilibrating the gels in noble metal salt solutions reduced with sodium borohydride, followed by supercritical drying. These porous aerogel fibers provide a platform for incorporating noble metals into silk fibroin materials, while also providing a new method to produce porous silk fibers. Noble metal silk aerogel fibers can be used for biological sensing and energy storage applications.

Download Full-text

Plasmon Assisted Highly Efficient Visible Light Catalytic CO2 Reduction Over the Noble Metal Decorated Sr-Incorporated g-C3N4

Nano-Micro Letters ◽

10.1007/s40820-021-00736-x ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Muhammad Humayun ◽

Habib Ullah ◽

Lang Shu ◽

Xiang Ao ◽

Asif Ali Tahir ◽

...

Keyword(s):

Visible Light ◽

Noble Metal ◽

Light Absorption ◽

Density Functional ◽

Noble Metals ◽

Resonance Effect ◽

Noble Metal Nanoparticles ◽

Localized Surface Plasmon ◽

High Quantum Efficiency ◽

Conversion Performance

AbstractThe photocatalytic performance of g-C3N4 for CO2 conversion is still inadequate by several shortfalls including the instability, insufficient solar light absorption and rapid charge carrier’s recombination rate. To solve these problems, herein, noble metals (Pt and Au) decorated Sr-incorporated g-C3N4 photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C3N4 band gap from 2.7 to 2.54 eV, as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO2 conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15Sr-CN sample produced 48.55 and 74.54 µmol h−1 g−1 of CH4 and CO, respectively. These amounts are far greater than that produced by the Au/0.15Sr-CN, 0.15Sr-CN, and CN samples. A high quantum efficiency of 2.92% is predicted for the Pt/0.15Sr-CN sample. Further, the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO2 conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance effect induced by noble metal nanoparticles. This work will provide a new approach for promoting the catalytic efficiency of g-C3N4 for efficient solar fuel production.

Download Full-text

A universal approach to the synthesis of nanodendrites of noble metals

Nanoscale ◽

10.1039/c4nr00421c ◽

2014 ◽

Vol 6 (11) ◽

pp. 6173-6179 ◽

Cited By ~ 21

Author(s):

Yan Feng ◽

Xiaohong Ma ◽

Lin Han ◽

Zhijian Peng ◽

Jun Yang

Keyword(s):

Metal Nanoparticles ◽

Noble Metal ◽

Noble Metals ◽

Noble Metal Nanoparticles ◽

Universal Approach ◽

Dendritic Structures

A universal approach was demonstrated for the synthesis of noble metal nanoparticles with dendritic structures.

Download Full-text

The in vitro effect of commercially available noble metal nanocolloids on the splenocyte proliferative response and cytokine production in mice

Polish Journal of Veterinary Sciences ◽

10.2478/pjvs-2014-0005 ◽

2014 ◽

Vol 17 (1) ◽

pp. 37-45 ◽

Cited By ~ 7

Author(s):

J. Małaczewska

Keyword(s):

Noble Metal ◽

Proliferative Activity ◽

Noble Metals ◽

Living Organism ◽

Reticuloendothelial System ◽

Noble Metal Nanoparticles ◽

Mouse Splenocytes ◽

Toxic Concentrations ◽

Vitro Effect

Abstract Noble metal nanoparticles, currently among the most popular types of nanomaterials, are capable of penetrating through biological barriers once they enter a living organism. There, they can permeate into organs possessing the reticuloendothelial system, such as the spleen. The objective of this study was to determine the effect of commercial nanocolloids of noble metals (silver, gold and copper), recommended by the manufacturer as dietary supplements, on the in vitro viability, proliferative activity and production of cytokines (IL-1β, IL-2, IL-6, IL- 10 and TNF-α) by mouse splenocytes. All of the analyzed colloids had some effect on the activity of mouse splenocytes. Silver colloid was characterized by high toxicity - concentrations of 1.25 ppm and above substantially depressed the viability of cells as well as their proliferative activity and ability to synthesize cytokines. The other two colloids were far less toxic than nanosilver, although their non-toxic concentrations had a significant effect on the production of cytokines by mitogen activated splenocytes. The colloid of gold decreased the level of IL-2, and the colloid of copper caused an increase in IL-2, IL6 and Il-10. At the same time, copper colloid alone induced the synthesis of IL-1β in mitogen unstimulated cells. The results indicate that colloids of noble metals are capable of affecting the activity of immunocompetent cells in important peripheral organs of the immune system.

Download Full-text

Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.5.251 ◽

2014 ◽

Vol 5 ◽

pp. 2413-2423 ◽

Cited By ~ 5

Author(s):

Rudolf Herrmann ◽

Markus Rennhak ◽

Armin Reller

Keyword(s):

Noble Metal ◽

Noble Metals ◽

Synthetic Methods ◽

Noble Metal Nanoparticles ◽

Synthesis And Characterization ◽

Core Shell ◽

Ceria Nanoparticles ◽

Thiol Groups ◽

Silica Core

The present review article covers work done in the cluster NPBIOMEM in the DFG priority programme SPP 1313 and focuses on synthesis and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core–shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the determination of the number of thiol groups and an estimate for the number of fluorescent molecules per nanoparticles, including a scattering correction, have been developed. Ceria nanoparticles decorated with noble metals (Pt, Pd, Rh) are models for the decomposition products of automobile catalytic converters which appear in the exhaust gases and finally interact with biological systems including humans. The control of the degree of agglomeration of small ceria nanoparticles is the basis for their synthesis. Almost monodisperse agglomerates (40 ± 4–260 ± 40 nm diameter) can be prepared and decorated with noble metal nanoparticles (2–5 nm diameter). Fluorescence labelling with ATTO 647N gave the model particles which are now under biophysical investigation.

Download Full-text