scholarly journals Highly Efficient Catalytic Performances of Nitro Compounds and Morin via Self-Assembled MXene-Pd Nanocomposites Synthesized through Self-Reduction Strategy

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1009 ◽  
Author(s):  
Juanjuan Yin ◽  
Lun Zhang ◽  
Tifeng Jiao ◽  
Guodong Zou ◽  
Zhenhua Bai ◽  
...  
Keyword(s):  
Reaction Times ◽  
High Energy ◽  
Nitro Compounds ◽  
Reduction Reaction ◽  
Future Research ◽  
Simple Method ◽  
Highly Efficient ◽  
New Type ◽  
Self Assembled ◽  
Catalytic Cycles

With development of the society, the problem of environmental pollution is becoming more and more serious. There is the urgent need to develop a new type of sustainable green material for degradable pollutants. However, the conventional preparation method is limited by conditions such as cumbersome operation, high energy consumption, and high pollution. Here, a simple method named self-reduction has been proposed, to synthesize highly efficient catalytic nitro compounds and morin self-assembled MXene-Pd nanocomposites. Palladium nanoparticles were grown in situ on MXene nanosheets to form MXene@PdNPs. MXene@PdNPs composites with different reaction times were prepared by adjusting the reduction reaction time. In particular, MXene@PdNPs20 exhibited a high catalytic effect on 4-NP and 2-NA, and the first-order rate constants of the catalysis were 0.180 s−1 and 0.089 s−1, respectively. It should be noted that after eight consecutive catalytic cycles, the conversion to catalyze 4-NP was still greater than 94%, and the conversion to catalyze 2-NA was still greater than 91.8%. Therefore, the research of self-assembled MXene@PdNPs nanocomposites has important potential value for environmental management and sustainable development of human health, and provides new clues for the future research of MXene-based new catalyst materials.

Strongly coupled ultrasmall-Fe7C3/N-doped porous carbon hybrids for highly efficient Zn–air batteries

2019 ◽  
Vol 55 (39) ◽  
pp. 5651-5654 ◽  
Author(s):  
Lulu Chen ◽  
Yelong Zhang ◽  
Xiangjian Liu ◽  
Ling Long ◽  
Siyu Wang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Porous Carbon ◽  
Reduction Reaction ◽  
Simple Method ◽  
Strongly Coupled ◽  
Highly Efficient ◽  
Zinc Air Batteries

This report presents a simple method to produce an ultrasmall-Fe7C3/N-doped porous carbon hybrid (u-Fe7C3@NC) as an excellent catalyst for oxygen reduction reaction and zinc–air batteries.

Recent Progress in Electrode Materials for Nonaqueous Lithium-Ion Capacitors

2020 ◽  
Vol 20 (5) ◽  
pp. 2652-2667 ◽  
Author(s):  
Juan Xu ◽  
Biao Gao ◽  
Kai-Fu Huo ◽  
Paul K. Chu
Keyword(s):  
Electrode Materials ◽  
Lithium Ion ◽  
High Energy ◽  
Future Research ◽  
Energy Storage Devices ◽  
Metal Compounds ◽  
Storage Devices ◽  
New Type ◽  
Low Dimensional ◽  
Power Densities

As a new type of energy-storage devices, lithium-ion capacitors (LICs) are designed to deliver high energy densities, high power densities, and long lifespan by integrating the battery-type anodes and capacitor-type cathodes. Achieving high energy and power density simultaneously is the challenge of LICs, which is mainly determined by the cathode and anode materials. In this mini-review, basing on the working principles of LICs, we discuss the categories and electrochemical performance as well as the matching strategies of the cathodes and anodes. In anodes, we focus on summarizing the structural design of the prelithiation transition-metal compounds based materials. In cathodes, we emphasize discussing the fabrication and morphology adjustment of the low dimensional carbon materials. Finally, the prospects and challenges confronting future research and development of LICs are provided.

Self-synergistic cobalt catalysts with symbiotic metal single-atoms and nanoparticles for efficient oxygen reduction

2021 ◽  
Author(s):  
Wu Zhou ◽  
Hui Su ◽  
Zijun Wang ◽  
Feng Yu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Cobalt Catalysts ◽  
Co Catalyst ◽  
Single Atoms ◽  
Highly Efficient ◽  
New Type ◽  
Oxygen Reduction Reaction Catalyst

A new type of self-synergistic Co catalyst consisting of symbiotic Co single-atoms and nanoparticles (S/Co-SA–NPs) is designed for use as a highly efficient oxygen reduction reaction catalyst.

Rapid Crystallization and Kinetic Freezing of Site-Disorder in the Lithium Superionic Argyrodite Li6PS5Br

2019 ◽  
Author(s):  
Ajay Gautam ◽  
Marcel Sadowski ◽  
Nils Prinz ◽  
Henrik Eickhoff ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Synthesis Method ◽  
Reaction Times ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
High Energy ◽  
Superionic Conductors ◽  
Rapid Crystallization ◽  
Site Disorder ◽  
Fast Cooling

<p>Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li<sub>6</sub>PS<sub>5</sub>X (X = Cl, Br, I), a site-disorder between the anionsS<sup>2–</sup>and X<sup>–</sup>has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such disorder in Li<sub>6</sub>PS<sub>5</sub>Br can be engineered <i>via</i>the synthesis method. By comparing fast cooling (<i>i.e. </i>quenching) to more slowly cooled samples, we find that anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with <i>ab-initio</i>molecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within one minute of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that long reaction times with high energy consumption are not needed in this class of materials. The fact that site-disorder induced <i>via</i>quenching is beneficial for ionic transport provides an additional approach for the optimization and design of lithium superionic conductors.</p>

Cut Flowers Being Sold as Impulse Items: A Look at Factors Affecting Impulse Product Merchandising

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 558c-558
Author(s):  
Jennifer B. Neujahr ◽  
Karen L.B. Gast
Keyword(s):  
Consumer Behavior ◽  
Marketing Strategies ◽  
Easy Access ◽  
Future Research ◽  
Grocery Stores ◽  
Cut Flowers ◽  
Factors Affecting ◽  
New Type ◽  
The 1950S ◽  
The Way

Consumer behavior research seems to play an big role in determining the wants and needs of an industry. This research helps to shape the way we market to the consumers and helps make marketing strategies more effective. In the 1950s grocery stores began to sell horticulture products in order to alleviate the growers' surplus. Supermarkets now have seem to found their niche in this market due to the fact that they can influence their consumers to buy their flowers right along with their bread, and get all of their shopping done at once. This new type of sale, commonly referred to as the impulse sale, can relate directly to how well the store is merchandised and maintained. A study was conducted at a local supermarket, to determine the following: good locations for impulse sales items, special conditions affecting impulse sales items, and what types of things could affect demand for impulse items. It was discovered that certain locations make better sales than other locations. Locations that were front and center and allowed easy access to seeing the mixed flower bouquet without having to touch it yielded the best results. The variables used to show a change in demand showed little to some variability and has raised some questions which may be used to conduct future research.

Hafnium(IV) Chloride Catalyzes Highly Efficient Acetalization of Carbonyl Compounds

2019 ◽  
Vol 16 (6) ◽  
pp. 913-920 ◽  
Author(s):  
Israel Bonilla-Landa ◽  
Emizael López-Hernández ◽  
Felipe Barrera-Méndez ◽  
Nadia C. Salas ◽  
José L. Olivares-Romero
Keyword(s):  
Microwave Heating ◽  
Reaction Times ◽  
Protecting Groups ◽  
Catalyst Loading ◽  
Selective Protection ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
High Yields ◽  
Novel Catalyst ◽  
Acid Labile

Background: Hafnium(IV) tetrachloride efficiently catalyzes the protection of a variety of aldehydes and ketones, including benzophenone, acetophenone, and cyclohexanone, to the corresponding dimethyl acetals and 1,3-dioxolanes, under microwave heating. Substrates possessing acid-labile protecting groups (TBDPS and Boc) chemoselectively generated the corresponding acetal/ketal in excellent yields. Aim and Objective: In this study. the selective protection of aldehydes and ketones using a Hafnium(IV) chloride, which is a novel catalyst, under microwave heating was observed. Hence, it is imperative to find suitable conditions to promote the protection reaction in high yields and short reaction times. This study was undertaken not only to find a novel catalyst but also to perform the reaction with substrates bearing acid-labile protecting groups, and study the more challenging ketones as benzophenone. Materials and Methods: Using a microwave synthesis reactor Monowave 400 of Anton Paar, the protection reaction was performed on a raging temperature of 100°C ±1, a pressure of 2.9 bar, and an electric power of 50 W. More than 40 substrates have been screened and protected, not only the aldehydes were protected in high yields but also the more challenging ketones such as benzophenone were protected. All the products were purified by simple flash column chromatography, using silica gel and hexanes/ethyl acetate (90:10) as eluents. Finally, the protected substrates were characterized by NMR 1H, 13C and APCI-HRMS-QTOF. Results: Preliminary screening allowed us to find that 5 mol % of the catalyst is enough to furnish the protected aldehyde or ketone in up to 99% yield. Also it was found that substrates with a variety of substitutions on the aromatic ring (aldehyde or ketone), that include electron-withdrawing and electrondonating group, can be protected using this methodology in high yields. The more challenging cyclic ketones were also protected in up to 86% yield. It was found that trimethyl orthoformate is a very good additive to obtain the protected acetophenone. Finally, the protection of aldehydes with sensitive functional groups was performed. Indeed, it was found that substrates bearing acid labile groups such as Boc and TBDPS, chemoselectively generated the corresponding acetal/ketal compound while keeping the protective groups intact in up to 73% yield. Conclusion: Hafnium(IV) chloride as a catalyst provides a simple, highly efficient, and general chemoselective methodology for the protection of a variety of structurally diverse aldehydes and ketones. The major advantages offered by this method are: high yields, low catalyst loading, air-stability, and non-toxicity.

Facile Synthesis of Cu2O nanoparticle-loaded Carbon Nanotubes Composite Catalysts for Reduction of 4-Nitrophenol

2020 ◽  
Vol 16 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Yao Feng ◽  
Ran Wang ◽  
Juanjuan Yin ◽  
Fangke Zhan ◽  
Kaiyue Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Stability ◽  
Catalytic Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Reaction ◽  
Cycle Performance ◽  
Simple Method ◽  
Composite Catalysts ◽  
Cu2o Nanoparticles

Background: 4-nitrophenol (4-NP) is one of the pollutants in sewage and harmful to human health and the environment. Cu is a non-noble metal with catalytic reduction effect on nitro compounds, and.has the advantages of simple preparation, abundant reserves, and low price. Carbon nanotubes (CNT) are widely used for substrate due to their excellent mechanical stability and high surface area. In this study, a simple method to prepare CNT-Cu2O by controlling different reaction time was reported. The prepared nanocomposites were used to catalyze 4-NP. Methods: CNTs and CuCl2 solution were put into a beaker, and then ascorbic acid and NaOH were added while continuously stirring. The reaction was carried out for a sufficiently long period of time at 60°C. The prepared samples were dried in a vacuum at 50°C for 48 h after washing with ethyl alcohol and deionized water. Results: Nanostructures of these composites were characterized by scanning electron microscope and transmission electron microscopy techniques, and the results at a magnification of 200 nanometers showed that Cu2O was distributed on the surface of the CNTs. In addition, X-ray diffraction was performed to further confirm the formation of Cu2O nanoparticles. The results of ultraviolet spectrophotometry showed that the catalytic effect of the compound on 4-NP was obvious. Conclusions: CNTs acted as a huge template for loading Cu2O nanoparticles, which could improve the stability and cycle performance of Cu2O. The formation of nanoparticles was greatly affected by temperature and the appropriate concentration, showing great reducibility for the 4-NP reduction reaction.

scholarly journals Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of “Branch-Leaf” Electrode for High-Energy Sodium–Sulfur Batteries

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Wenyan Du ◽  
Kangqi Shen ◽  
Yuruo Qi ◽  
Wei Gao ◽  
Mengli Tao ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Electrochemical Reaction ◽  
Molecular Layer ◽  
Specific Capacity ◽  
High Energy ◽  
Reduction Reaction ◽  
Biomimetic Design ◽  
Co Nanoparticles ◽  
Sodium Sulfur

AbstractRechargeable room temperature sodium–sulfur (RT Na–S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D “branch-leaf” biomimetic design proposed for high performance Na–S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive “branches” to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D “branch-leaf” conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared “branch-leaf” CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g−1 at 0.1 C and superior rate performance.

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