scholarly journals Halide-regulated growth of electrocatalytic metal nanoparticles directly onto a carbon paper electrode

2016 ◽  
Vol 4 (43) ◽  
pp. 17154-17162 ◽  
Author(s):  
Yaovi Holade ◽  
David P. Hickey ◽  
Shelley D. Minteer
Keyword(s):  
Metal Nanoparticles ◽  
Catalytic Efficiency ◽  
Metal Particles ◽  
Carbon Paper ◽  
Wide Range ◽  
Direct Growth ◽  
Nanostructured Metal

Direct growth of hierarchical micro/nanostructured metal arrays on a 3D substrate is a powerful tool to enhance the catalytic efficiency of metal particles towards a wide range of substrates.

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur
Keyword(s):  
Supramolecular Chemistry ◽  
Sulfonic Acid ◽  
Catalytic Efficiency ◽  
The Other ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bioactive Scaffolds ◽  
Wide Range ◽  
Efficient Alternative ◽  
Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

scholarly journals Synthesis of Micro- and Nanoparticles in Sub- and Supercritical Water: From the Laboratory to Larger Scales

2020 ◽  
Vol 10 (16) ◽  
pp. 5508
Author(s):  
F. Ruiz-Jorge ◽  
J. R. Portela ◽  
J. Sánchez-Oneto ◽  
E. J. Martínez de la Ossa
Keyword(s):  
Supercritical Fluids ◽  
Supercritical Water ◽  
Metal Particles ◽  
High Pressure And Temperature ◽  
Particle Generation ◽  
Innovative Method ◽  
Wide Range ◽  
Active Research ◽  
Main Operating ◽  
Temperature Water

The use of micro- and nanoparticles is gaining more and more importance because of their wide range of uses and benefits based on their unique mechanical, physical, electrical, optical, electronic, and magnetic properties. In recent decades, supercritical fluid technologies have strongly emerged as an effective alternative to other numerous particle generation processes, mainly thanks to the peculiar properties exhibited by supercritical fluids. Carbon dioxide and water have so far been two of the most commonly used fluids for particle generation, the former being the fluid par excellence in this field, mainly, because it offers the possibility of precipitating thermolabile particles. Nevertheless, the use of high-pressure and -temperature water opens an innovative and very interesting field of study, especially with regards to the precipitation of particles that could hardly be precipitated when CO2 is used, such as metal particles with a considerable value in the market. This review describes an innovative method to obtain micro- and nanoparticles: hydrothermal synthesis by means of near and supercritical water. It also describes the differences between this method and other conventional procedures, the most currently active research centers, the types of particles synthesized, the techniques to evaluate the products obtained, the main operating parameters, the types of reactors, and amongst them, the most significant and the most frequently used, the scaling-up studies under progress, and the milestones to be reached in the coming years.

Direct growth of flower-like 3D MnO2 ultrathin nanosheets on carbon paper as efficient cathode catalyst for rechargeable Li–O2 batteries

RSC Advances ◽  
2015 ◽  
Vol 5 (89) ◽  
pp. 72495-72499 ◽  
Author(s):  
Hong-Qiang Wang ◽  
Jing Chen ◽  
Si-Jiang Hu ◽  
Xiao-Hui Zhang ◽  
Xiao-Ping Fan ◽  
...  
Keyword(s):  
Carbon Paper ◽  
Cathode Catalyst ◽  
Working Mechanism ◽  
Air Electrode ◽  
Ultrathin Nanosheets ◽  
Direct Growth

Structure and working mechanism of the MnO2/CP air electrode.

scholarly journals Biosynthesis, purification, characterization and immobilization of laccase from Lithothelium sp.

Chemija ◽  
2020 ◽  
Vol 31 (3) ◽  
Author(s):  
Ingrida Radveikienė ◽  
Ingrida Pilotaitė ◽  
Rimgailė Dainytė ◽  
Regina Vidžiūnaitė
Keyword(s):  
Residual Activity ◽  
Catalytic Efficiency ◽  
Hydrophobic Interaction Chromatography ◽  
Metal Salts ◽  
Biotechnological Applications ◽  
Affinity Constants ◽  
Sds Page ◽  
Wide Range ◽  
Optimum Ph ◽  
Sulphate Salts

Novel fungal laccase isoenzymes (namely L95-1 and L95-2) produced by the Ascomycete Lithothelium sp. isolated from the forest soil were purified. However, only one of them was characterized, because the other isoenzyme lost its activity during purification. Extracellular L95-1 laccase was purified 30-fold using ion-exchange and hydrophobic interaction chromatography, with an overall yield of 88%. The molecular mass of purified L95-1 was estimated to be 85 kDa by SDS-PAGE analysis. L95-1 laccase was stable at temperature 4–22°C and pH 6.0–6.5. The substrate specificity of L95-1 laccase was examined with various compounds. Determined affinity constants (KM) varied in a wide range of 3.7–2020.0 µM, whereas catalytic efficiency constants (kcat/KM) covered a range of 0.008–1.9 µM–1 s–1. The optimum pH for most substrates varied in a range from pH 5.0 to 6.0. Sodium azide and fluoride strongly inhibited L95-1 activity, whereas sulphate salts inhibited weakly. The laccase was immobilized on the Fe3O4 nanoparticles and characterized. Residual activity remained at 20% after ten cycles of ABTS oxidation reaction. The immobilized laccase showed higher tolerance to various metal salts. The properties of L95-1 laccase make it potentially useful in the biotechnological applications.

scholarly journals Application of fungal copper carbonate nanoparticles as environmental catalysts: organic dye degradation and chromate removal

Microbiology ◽  
2021 ◽  
Vol 167 (12) ◽  
Author(s):  
Feixue Liu ◽  
Dinesh Singh Shah ◽  
Laszlo Csetenyi ◽  
Geoffrey Michael Gadd
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Dye Degradation ◽  
Antibacterial Properties ◽  
Toxic Metal ◽  
Catalytic Efficiency ◽  
Methyl Red ◽  
Copper Carbonate ◽  
Wide Range ◽  
Organic Dye Degradation

Biomineralization is a ubiquitous process in organisms to produce biominerals, and a wide range of metallic nanoscale minerals can be produced as a consequence of the interactions of micro-organisms with metals and minerals. Copper-bearing nanoparticles produced by biomineralization mechanisms have a variety of applications due to their remarkable catalytic efficiency, antibacterial properties and low production cost. In this study, we demonstrate the biotechnological potential of copper carbonate nanoparticles (CuNPs) synthesized using a carbonate-enriched biomass-free ureolytic fungal spent culture supernatant. The efficiency of the CuNPs in pollutant remediation was investigated using a dye (methyl red) and a toxic metal oxyanion, chromate Cr(VI). The biogenic CuNPs exhibited excellent catalytic properties in a Fenton-like reaction to degrade methyl red, and efficiently removed Cr(VI) from solution due to both adsorption and reduction of Cr(VI). X-ray photoelectron spectroscopy (XPS) identified the oxidation of reducing Cu species of the CuNPs during the reaction with Cr(VI). This work shows that urease-positive fungi can play an important role not only in the biorecovery of metals through the production of insoluble nanoscale carbonates, but also provides novel and simple strategies for the preparation of sustainable nanomineral products with catalytic properties applicable to the bioremediation of organic and metallic pollutants, solely and in mixtures.

scholarly journals Application of biosynthesized metal nanoparticles in electrochemical sensors

2021 ◽  
pp. 77-77
Author(s):  
Totka Dodevska ◽  
Dobrin Hadzhiev ◽  
Ivan Shterev ◽  
Yanna Lazarova
Keyword(s):  
Green Synthesis ◽  
Metal Nanoparticles ◽  
Electrochemical Sensors ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Electrochemical Sensing ◽  
Synthesis Methods ◽  
Range Limit ◽  
Wide Range

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered. Keywords: biosynthesis; green synthesis; nanomaterials; nanotechnology; modified electrodes

scholarly journals Polynuclear Cobalt Complexes as Catalysts for Light-Driven Water Oxidation: A Review of Recent Advances

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 602 ◽  
Author(s):  
Dmytro Nesterov ◽  
Oksana Nesterova
Keyword(s):  
Water Oxidation ◽  
Catalytic Efficiency ◽  
Cobalt Complexes ◽  
Platinum Group Metal ◽  
Experimental Methods ◽  
Cobalt Ions ◽  
Recent Advances ◽  
Wide Range ◽  
Artificial Photosynthetic ◽  
Molecular Catalysts

Photochemical water oxidation, as a half-reaction of water splitting, represents a great challenge towards the construction of artificial photosynthetic systems. Complexes of first-row transition metals have attracted great attention in the last decade due to their pronounced catalytic efficiency in water oxidation, comparable to that exhibited by classical platinum-group metal complexes. Cobalt, being an abundant and relatively cheap metal, has rich coordination chemistry allowing construction of a wide range of polynuclear architectures for the catalytic purposes. This review covers recent advances in application of cobalt complexes as (pre)catalysts for water oxidation in the model catalytic system comprising [Ru(bpy)3]2+ as a photosensitizer and S2O82− as a sacrificial electron acceptor. The catalytic parameters are summarized and discussed in view of the structures of the catalysts. Special attention is paid to the degradation of molecular catalysts under catalytic conditions and the experimental methods and techniques used to control their degradation as well as the leaching of cobalt ions.

scholarly journals Two-Dimensional Optical Metasurfaces: From Plasmons to Dielectrics

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Bo Liu ◽  
Kerui Song ◽  
Jiangnan Xiao
Keyword(s):  
Metal Particles ◽  
Subwavelength Structures ◽  
Metal Structures ◽  
Unit Structure ◽  
Wide Range ◽  
Different Types ◽  
Working Principle ◽  
Physical Fields ◽  
Near Future ◽  
Polarization Phase

Metasurfaces, kinds of planar ultrathin metamaterials, are able to modify the polarization, phase, and amplitude of physical fields of optical light by designed periodic subwavelength structures, attracting great interest in recent years. Based on the different type of the material, optical metasurfaces can be separated in two categories by the materials: one is metal and the other is dielectric. Metal metasurfaces rely on the surface plasma oscillations of subwavelength metal particles. Nevertheless, the loss caused by the metal structures has been a trouble, especially for devices working in transmit modes. The dielectric metasurfaces are based on the Faraday-Tyndall scattering of high-index dielectric light scattering particles. By reasonably designing the relevant parameters of the unit structure such as the size, direction, and shape, different functions of metasurfaces can realize and bring a wide range of applications. This article focuses on the metasurface concepts such as anomalous reflections and refractions and the working principle of different types of metasurfaces. Here, we briefly review the progress in developing optical over past few years and look into the near future.

scholarly journals Microorganism Assisted Synthesized Nanoparticles for Catalytic Applications

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 190 ◽  
Author(s):  
Xiaojiao Fang ◽  
Yin Wang ◽  
Zegao Wang ◽  
Zaixing Jiang ◽  
Mingdong Dong
Keyword(s):  
Energy Consumption ◽  
Environmental Remediation ◽  
Heterogeneous Catalysts ◽  
Catalytic Efficiency ◽  
High Energy ◽  
Surface Areas ◽  
Novel Approach ◽  
Toxic Agents ◽  
Wide Range ◽  
Catalytic Applications

Metal and metalloid nanoparticles (NPs) have attracted substantial attention from research communities over the past few decades. Traditional methodologies for NP fabrication have also been intensely explored. However, drawbacks such as the use of toxic agents and the high energy consumption involved in chemical and physical processes hinder their further application in various fields. It is well known that some bacteria are capable of binding and concentrating dissolved metal and metalloid ions, thereby detoxifying their environments. Bioinspired fabrication of NPs is environmentally friendly and inexpensive and requires only low energy consumption. Some biosynthesized NPs are usually used as heterogeneous catalysts in environmental remediation and show higher catalytic efficiency because of their enhanced biocompatibility, stability and large specific surface areas. Therefore, bacteria used as nanofactories can provide a novel approach for removing metal or metalloid ions and fabricating materials with unique properties. Even though a wide range of NPs have been biosynthesized, and their synthetic mechanisms have been proposed, some of these mechanisms are not known in detail. This review focuses on the synthesis and catalytic applications of NPs obtained using bacteria. The known mechanisms of bioreduction and prospects in the design of NPs for catalytic applications are also discussed.

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