scholarly journals Mechanistic insight into deep holes from interband transitions in Palladium nanoparticle photocatalysts

2021 ◽  
Author(s):  
Pin Lyu ◽  
Randy Espinoza ◽  
Md. Imran Khan ◽  
William C. Spaller ◽  
Sayantani Ghosh ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Aryl Halide ◽  
Localized Surface Plasmon ◽  
Quantum Yields ◽  
Mechanistic Study ◽  
Hot Electron ◽  
Interband Transitions ◽  
Electron Transfer Mechanism ◽  
Pd Nanoparticle

Photocatalysis of metallic nanoparticles, especially utilizing hot electrons generated from localized surface plasmon resonance, is of widespread interest. However, the role of hot holes, especially generated from interband transitions, has not been emphasized in exploring the photocatalytic mechanism yet. In this study, a photocatalyzed Suzuki-Miyaura reaction using mesoporous Pd nanoparticle photocatalyst served as a model reaction to study the role of hot holes by accurately measuring the quantum yields of the photocatalyst. The quantum yields increase under shorter wavelength excitations and correlate to the “deeper” energy of the holes from the Fermi level. Our mechanistic study suggests that deeper holes in the d-band can catalyze the oxidative addition of aryl halide R-X onto Pd0 at the surface of nanoparticles to form the R-PdII-X complex, the rate-determining step of the established catalytic cycle. We pointed out that this deep hole mechanism should deserve as much attention as the well-known hot electron transfer mechanism in previous studies.

scholarly journals Hot Electrons in TiO2–Noble Metal Nano-Heterojunctions: Fundamental Science and Applications in Photocatalysis

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1249
Author(s):  
Ajay P. Manuel ◽  
Karthik Shankar
Keyword(s):  
Noble Metal ◽  
Focal Point ◽  
Solar Spectrum ◽  
Metal Nanoparticle ◽  
Hot Electrons ◽  
Localized Surface Plasmon ◽  
Quantum Yields ◽  
Hot Electron ◽  
Interband Transitions ◽  
Metal Metal

Plasmonic photocatalysis enables innovation by harnessing photonic energy across a broad swathe of the solar spectrum to drive chemical reactions. This review provides a comprehensive summary of the latest developments and issues for advanced research in plasmonic hot electron driven photocatalytic technologies focusing on TiO2–noble metal nanoparticle heterojunctions. In-depth discussions on fundamental hot electron phenomena in plasmonic photocatalysis is the focal point of this review. We summarize hot electron dynamics, elaborate on techniques to probe and measure said phenomena, and provide perspective on potential applications—photocatalytic degradation of organic pollutants, CO2 photoreduction, and photoelectrochemical water splitting—that benefit from this technology. A contentious and hitherto unexplained phenomenon is the wavelength dependence of plasmonic photocatalysis. Many published reports on noble metal-metal oxide nanostructures show action spectra where quantum yields closely follow the absorption corresponding to higher energy interband transitions, while an equal number also show quantum efficiencies that follow the optical response corresponding to the localized surface plasmon resonance (LSPR). We have provided a working hypothesis for the first time to reconcile these contradictory results and explain why photocatalytic action in certain plasmonic systems is mediated by interband transitions and in others by hot electrons produced by the decay of particle plasmons.

Green synthesis of silver nanoparticles using sustainable resources and their use as antibacterial agents: A review

2020 ◽  
Vol 13 ◽  
Author(s):  
Kumari Jyoti ◽  
Punyasloka Pattnaik ◽  
Tej Singh
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extracts ◽  
Metallic Nanoparticles ◽  
Cost Effective ◽  
Biological Properties ◽  
Metal Species ◽  
Sustainable Resources ◽  
Research Areas ◽  
Low Toxicity

Background:: Synthesis of metallic nanoparticles has attracted extensive vitality in numerous research areas such as drug delivery, biomedicine, catalysis etc. where continuous efforts are being made by scientists and engineers to investigate new dimensions for both technological and industrial advancements. Amongst numerous metallic nanoparticles, silver nanoparticle (AgNPs) is a novel metal species with low toxicity, higher stability and significant chemical, physical and biological properties. Methods:: In this, various methods for the fabrication of AgNPs are summarized. Importantly, we concentrated on the role of reducing agents of different plants parts, various working conditions such as AgNO3 concentration; ratio of AgNO3/extract; incubation time; centrifugal conditions, size and shapes. Results:: This study suggested that eco-friendly and non toxic biomolecules present in the extracts (e.g. leaf, stem and root) of plants are used as reducing and capping agents for silver nanoparticles fabrication. This method of fabrication of silver nanoparticles using plants extracts is comparatively cost-effective and simple. A silver salt is simply reduced by biomolecules present in the extracts of these plants. In this review, we have emphasized the synthesis and antibacterial potential of silver nanoparticles using various plant extracts. Conclusion:: Fabrication of silver nanoparticles using plant extracts have advantage over the other physical methods, as it is safe, eco-friendly and simple to use. Plants have huge potential for the fabrication of silver nanoparticles of wide potential of applications with desired shape and size.

Improving peroxymonosulfate activation by copper ion-saturated adsorbent-based single atom catalysts for the degradation of organic contaminants: electron-transfer mechanism and the key role of Cu single atoms

2021 ◽  
Author(s):  
Jingwen Pan ◽  
Baoyu Gao ◽  
Pijun Duan ◽  
Kangying Guo ◽  
Muhammad Akram ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Organic Contaminants ◽  
High Salinity ◽  
Copper Ion ◽  
Single Atom ◽  
Electron Transfer Mechanism ◽  
Persulfate Oxidation ◽  
Single Atoms ◽  
Oxidation Technology

Nonradical pathway-based persulfate oxidation technology is considered to be a promising method for high-salinity organic wastewater treatment.

scholarly journals Pd Nanoparticles Stabilized by Hypercrosslinked Polystyrene Catalyze Selective Triple C-C Bond Hydrogenation and Suzuki Cross-Coupling

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Linda Zh. Nikoshvili ◽  
Nadezhda A. Nemygina ◽  
Tatiana E. Khudyakova ◽  
Irina Yu. Tiamina ◽  
Alexey V. Bykov ◽  
...  
Keyword(s):  
Phase Transfer ◽  
Aryl Halide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Pd Nanoparticles ◽  
Hypercrosslinked Polystyrene ◽  
Reductive Activation ◽  
Pd Nanoparticle ◽  
Cross Coupling Reaction ◽  
Precursor Decomposition

This paper describes the synthesis of Pd-containing catalysts based on nonfunctionalized hypercrosslinked polystyrene via impregnation with Pd acetate. Developed Pd nanoparticulate catalyst allowed achieving conversion of aryl halide up to 90% in Suzuki cross-coupling reaction under mild conditions and at the absence of phase-transfer agents. During the selective hydrogenation of triple C-C bond of 2-methyl-3-butyn-2-ol, up to 96% selectivity with respect to corresponding olefinic alcohol was found at 95% conversion. The influences of the procedure of catalyst synthesis like precursor decomposition and reductive activation method on Pd nanoparticle formation are discussed.

scholarly journals All-dielectric chiral-field-enhanced Raman optical activity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ting-Hui Xiao ◽  
Zhenzhou Cheng ◽  
Zhenyi Luo ◽  
Akihiro Isozaki ◽  
Kotaro Hiramatsu ◽  
...  
Keyword(s):  
Optical Activity ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Localized Surface Plasmon ◽  
Chiral Field ◽  
Resonance Spectroscopy ◽  
Conformational Structure ◽  
Dark Mode ◽  
Spontaneous Raman Scattering ◽  
Raman Optical Activity

AbstractRaman optical activity (ROA) is effective for studying the conformational structure and behavior of chiral molecules in aqueous solutions and is advantageous over X-ray crystallography and nuclear magnetic resonance spectroscopy in sample preparation and cost performance. However, ROA signals are inherently minuscule; 3–5 orders of magnitude weaker than spontaneous Raman scattering due to the weak chiral light–matter interaction. Localized surface plasmon resonance on metallic nanoparticles has been employed to enhance ROA signals, but suffers from detrimental spectral artifacts due to its photothermal heat generation and inability to efficiently transfer and enhance optical chirality from the far field to the near field. Here we demonstrate all-dielectric chiral-field-enhanced ROA by devising a silicon nanodisk array and exploiting its dark mode to overcome these limitations. Specifically, we use it with pairs of chemical and biological enantiomers to show >100x enhanced chiral light–molecule interaction with negligible artifacts for ROA measurements.

Boosting the Electrochemistry of Li2O2 in Lithium−Oxygen Batteries by Plasmon-induced Hot-Electron Injection

2021 ◽  
Author(s):  
Weixue Yang ◽  
Fei Li ◽  
Huali Liu ◽  
Zhen Li ◽  
Jiaqi Zhao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Localized Surface Plasmon ◽  
Hot Electron ◽  
Au Nps ◽  
Hot Electron Injection ◽  
Lithium Oxygen Batteries

A photo-assisted Li−Oxygen (Li−O2) battery with Au/SnO2 (ASO) hybrid nanotubes as cathode and photocatalyst has been prepared. The localized surface plasmon resonance (LSPR) excitation of gold nanoparticles (Au NPs) can...

scholarly journals Metallic Nanoparticles Obtained via “Green” Synthesis as a Platform for Biosensor Construction

2019 ◽  
Vol 9 (4) ◽  
pp. 720 ◽  
Author(s):  
Galina Gayda ◽  
Olha Demkiv ◽  
Nataliya Stasyuk ◽  
Roman Serkiz ◽  
Maksym Lootsik ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Metallic Nanoparticles ◽  
Alcohol Oxidase ◽  
Inorganic Ions ◽  
Special Role ◽  
Graphite Electrodes ◽  
Fluorescent Markers ◽  
Extracellular Metabolites ◽  
Very High

Novel nanomaterials, including metallic nanoparticles obtained via green synthesis (gNPs), have a great potential for application in biotechnology, industry and medicine. The special role of gNPs is related to antibacterial agents, fluorescent markers and carriers for drug delivery. However, application of gNPs for construction of amperometric biosensors (ABSs) is not well documented. The aim of the current research was to study potential advantages of using gNPs in biosensorics. The extracellular metabolites of the yeast Ogataea polymorpha were used as reducing agents for obtaining gNPs from the corresponding inorganic ions. Several gNPs were synthesized, characterized and tested as enzyme carriers on the surface of graphite electrodes (GEs). The most effective were Pd-based gNPs (gPdNPs), and these were studied further and applied for construction of laccase- and alcohol oxidase (AO)-based ABSs. AO/GE, AO-gPdNPs/GE, laccase/GE and laccase-gPdNPs/GE were obtained, and their analytical characteristics were studied. Both gPdNPs-modified ABSs were found to have broader linear ranges and higher storage stabilities than control electrodes, although they are less sensitive toward corresponding substrates. We thus conclude that gPdNPs may be promising for construction of ABSs for enzymes with very high affinities to their substrates.

The critical role of light in moderating microbial stress due to mixtures of engineered nanomaterials

2018 ◽  
Vol 5 (1) ◽  
pp. 96-102 ◽  
Author(s):  
Carolyn M. Wilke ◽  
Jean-François Gaillard ◽  
Kimberly A. Gray
Keyword(s):  
Critical Role ◽  
Engineered Nanomaterials ◽  
Metal Nanoparticle ◽  
Toxic Effects ◽  
Solar Irradiation ◽  
Localized Surface Plasmon ◽  
E Coli ◽  
Simulated Solar Irradiation ◽  
Role Of Light

Light influences chemical interactions of engineered nanomaterials and their toxic effects. Under simulated solar irradiation, we observed that binary mixtures of n-Ag, n-Au, or n-Pt with n-TiO2cause synergistic toxic effects inE. colidue to photochemical interactions governed by metal nanoparticle stability and localized surface plasmon resonance.

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