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

Metals ◽  
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.

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

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 107 ◽  
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.

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.

A universal approach to the synthesis of nanodendrites of noble metals

Nanoscale ◽  
2014 ◽  
Vol 6 (11) ◽  
pp. 6173-6179 ◽  
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.

Surface state modulation for size-controllable photodeposition of noble metal nanoparticles on semiconductors

2020 ◽  
Vol 8 (40) ◽  
pp. 21094-21102
Author(s):  
Lei Huang ◽  
Xiu Liu ◽  
Haocheng Wu ◽  
Xiuli Wang ◽  
Hongmin Wu ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Surface State ◽  
Noble Metals ◽  
Surface States ◽  
Noble Metal Nanoparticles ◽  
Size Distributions

The size distributions of noble metals on semiconductors can be precisely controlled by the photodeposition method with modulated surface states.

A seed-mediated approach to the general and mild synthesis of non-noble metal nanoparticles stabilized by a metal–organic framework for highly efficient catalysis

2015 ◽  
Vol 2 (6) ◽  
pp. 606-612 ◽  
Author(s):  
Yu-Zhen Chen ◽  
Linfeng Liang ◽  
Qihao Yang ◽  
Maochun Hong ◽  
Qiang Xu ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Noble Metals ◽  
Metal Organic Framework ◽  
Catalytic Performance ◽  
Noble Metal Nanoparticles ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Metal Organic ◽  
Seed Mediated

A novel noble metal-seed-mediated approach to reduce non-noble metals under mild conditions to afford non-noble metal NPs with superior catalytic performance.

scholarly journals Visible Light-Mediated Sustainable Antibacterial Activity and Osteogenic Functionality of Au and Pt Multi-Coated TiO2 Nanotubes

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5976
Author(s):  
Kyoung-Suk Moon ◽  
Young-Bum Park ◽  
Ji-Myung Bae ◽  
Eun-Joo Choi ◽  
Seung-Han Oh
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Metal Nanoparticles ◽  
Noble Metal ◽  
Noble Metals ◽  
Human Mesenchymal Stem Cells ◽  
Antibacterial Activities ◽  
Titania Nanotubes ◽  
Noble Metal Nanoparticles ◽  
Low Level Laser Therapy

The visible light reactions of noble metal-based photocatalysts have been increasingly utilized to investigate their antibacterial activities. Furthermore, the photoreactions at various visible light wavelengths for specific combinations of titania nanotubes and noble metal nanoparticles have been found to promote osteogenic functionality. In this investigation, a novel multi-coating combination of noble metals (gold and platinum) on titania nanotubes was assessed using plasmonic photocatalysis and low-level laser therapy at 470 and 600 nm. The results showed that this coating on the nanotubes promoted antibacterial activity and osteogenic functionality. The order in which the gold and platinum coatings were layered onto the titania nanotubes strongly affected the osteogenic performance of the human mesenchymal stem cells. These results have identified a new approach for the development of efficient novel combinations of noble metal nanoparticles and titania nanotubes with visible light responses, sustainable antimicrobial activity, and osteogenic functionality.

scholarly journals Synthesis of Au or Pt@Perovskite Nanocrystals via Interfacial Photoreduction

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 174
Author(s):  
Jing Zhang ◽  
Li Wang ◽  
Wenwen Liu ◽  
Mengsha Cao ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Perovskite Phase ◽  
Pt Nanoparticles ◽  
Noble Metal Nanoparticles ◽  
Great Promise ◽  
Face Centered Cubic ◽  
Time Resolved ◽  
Perovskite Nanocrystals ◽  
Average Size

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.

scholarly journals Morphology, Photocatalytic and Antimicrobial Properties of TiO2 Modified with Mono- and Bimetallic Copper, Platinum and Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1129 ◽  
Author(s):  
Izabela Wysocka ◽  
Ewa Kowalska ◽  
Jacek Ryl ◽  
Grzegorz Nowaczyk ◽  
Anna Zielińska-Jurek
Keyword(s):  
Photocatalytic Activity ◽  
Metal Nanoparticles ◽  
Noble Metal ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Diffuse Reflectance Spectroscopy ◽  
Action Spectrum ◽  
Noble Metal Nanoparticles ◽  
Biocidal Activity ◽  
X Ray

Noble metal nanoparticles (NMNPs) enhanced TiO2 response and extended its activity under visible light. Photocatalytic activity of TiO2 modified with noble metal nanoparticles strongly depends on the physicochemical properties of NMNPs. Among others, the differences in the size of NMNPs seems to be one of the most important factors. In this view, the effect of the metal’s nanoparticles size, type and amount on TiO2 photocatalytic and biocidal activity was investigated. TiO2 modified with mono- and bimetallic nanoparticles of Pt, Cu and Ag were prepared using chemical and thermal reduction methods. Obtained nanocomposites were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and diffuse-reflectance spectroscopy (DR/UV-Vis) techniques. The photocatalytic activity was examined in 2-propanol oxidation and hydrogen generation processes. The mechanism of modified TiO2 excitation was evaluated in action spectrum measurements during phenol oxidation. A possibility of using less energy-consuming light sources as a set of light-emitting diodes (LEDs) selected based on action spectrum results was examined. It was found that the differences in NMNPs size were the result of the reduction method. Moreover, coupling with a second metal strongly affected and differentiated the photocatalytic and biocidal activity of the obtained TiO2-based photocatalysts.

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