2D MXenes as Co-catalysts in Photocatalysis: Synthetic Methods

Abstract Since their seminal discovery in 2011, two-dimensional (2D) transition metal carbides/nitrides known as MXenes, that constitute a large family of 2D materials, have been targeted toward various applications due to their outstanding electronic properties. MXenes functioning as co-catalyst in combination with certain photocatalysts have been applied in photocatalytic systems to enhance photogenerated charge separation, suppress rapid charge recombination, and convert solar energy into chemical energy or use it in the degradation of organic compounds. The photocatalytic performance greatly depends on the composition and morphology of the photocatalyst, which, in turn, are determined by the method of preparation used. Here, we review the four different synthesis methods (mechanical mixing, self-assembly, in situ decoration, and oxidation) reported for MXenes in view of their application as co-catalyst in photocatalysis. In addition, the working mechanism for MXenes application in photocatalysis is discussed and an outlook for future research is also provided.

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Biomimetic Cu/Nitroxyl Catalyst Systems for Selective Alcohol Oxidation

Catalysts ◽

10.3390/catal9050395 ◽

2019 ◽

Vol 9 (5) ◽

pp. 395 ◽

Cited By ~ 7

Author(s):

Lindie Marais ◽

Andrew John Swarts

Keyword(s):

Active Sites ◽

Alcohol Oxidation ◽

Galactose Oxidase ◽

Co Catalyst ◽

Co Catalysts ◽

Mechanistic Pathway ◽

Oxidation Of Alcohols ◽

Catalyst Systems ◽

Carbonyl Products

The oxidation of alcohols to the corresponding carbonyl products is an important organic transformation and the products are used in a variety of applications. The development of catalytic methods for selective alcohol oxidation have garnered significant attention in an attempt to find a more sustainable method without any limitations. Copper, in combination with 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO) and supported by organic ligands, have emerged as the most effective catalysts for selective alcohol oxidation and these catalyst systems are frequently compared to galactose oxidase (GOase). The efficiency of GOase has led to extensive research to mimic the active sites of these enzymes, leading to a variety of Cu/TEMPO· catalyst systems being reported over the years. The mechanistic pathway by which Cu/TEMPO· catalyst systems operate has been investigated by several research groups, which led to partially contradicting mechanistic description. Due to the disadvantages and limitations of employing TEMPO· as co-catalyst, alternative nitroxyl radicals or in situ formed radicals, as co-catalysts, have been successfully evaluated in alcohol oxidation. Herein we discuss the development and mechanistic elucidation of Cu/TEMPO· catalyst systems as biomimetic alcohol oxidation catalysts.

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Visualization of Iron-Binding Micelles in Acidic Recombinant Biomineralization Protein, MamC

Journal of Nanomaterials ◽

10.1155/2014/320124 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 12

Author(s):

Sanjay Kashyap ◽

Taylor Woehl ◽

Carmen Valverde-Tercedor ◽

Miguel Sánchez-Quesada ◽

Concepción Jiménez López ◽

...

Keyword(s):

Low Temperature ◽

Self Assembly ◽

Inorganic Nanoparticles ◽

The Self ◽

Synthetic Methods ◽

Biological Macromolecules ◽

Iron Binding ◽

Precise Control ◽

Iron Binding Protein

Biological macromolecules are utilized in low-temperature synthetic methods to exert precise control over nanoparticle nucleation and placement. They enable low-temperature formation of a variety of functional nanostructured materials with properties often not achieved via conventional synthetic techniques. Here we report on thein situvisualization of a novel acidic bacterial recombinant protein, MamC, commonly present in the magnetosome membrane of several magnetotactic bacteria, includingMagnetococcus marinus, strain MC-1. Our findings provide an insight into the self-assembly of MamC and point to formation of the extended protein surface, which is assumed to play an important role in the formation of biotemplated inorganic nanoparticles. The self-organization of MamC is compared to the behavior of another acidic recombinant iron-binding protein, Mms6.

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Synthesis and Self-Assembly of Conjugated Block Copolymers

Polymers ◽

10.3390/polym13010110 ◽

2020 ◽

Vol 13 (1) ◽

pp. 110

Author(s):

Lin-Lin Xiao ◽

Xu Zhou ◽

Kan Yue ◽

Zi-Hao Guo

Keyword(s):

Thin Film ◽

Block Copolymers ◽

Conjugated Polymers ◽

Self Assembly ◽

The Self ◽

Synthetic Methods ◽

Future Research ◽

Structural Factors ◽

The Past ◽

Different Types

In the past two decades, conjugated polymers (CPs) have drawn great attention due to their excellent conductivity and charge mobility, rendering them broad applications in organic electronics. Controlling over the morphologies and nanostructures of CPs is very important to improve the performance of CP-based devices, which is still a tremendously difficult task. Conjugated block copolymers (cBCPs), composed of different CP blocks or CP coupled with coiled polymeric blocks, not only maintain the advantages of high conductivity and mobility but also demonstrate features of morphological versatility and tunability. Due to the strong π–π interaction and crystallinity of the conjugated backbones, the self-assembly behaviors of cBCPs are very complicated and largely remain to be explored. In this tutorial review, we first summarize the general synthetic methods for different types of cBCPs. Then, recent studies on the self-assembly behaviors of cBCPs are discussed, with an emphasis on the structural factors that affect the morphologies of cBCPs both in bulk and thin film states. Finally, we briefly provide our outlook on the future research of the self-assembly of cBCPs.

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Emerging Topochemical Strategies for Designing Two-Dimensional Energy Materials

Micromachines ◽

10.3390/mi12080867 ◽

2021 ◽

Vol 12 (8) ◽

pp. 867

Author(s):

Na Liu ◽

Libo Chang ◽

Jiang Wu ◽

Jianhua Fang ◽

Xu Xiao

Keyword(s):

Material Properties ◽

High Efficiency ◽

2D Materials ◽

Synthetic Methods ◽

Future Research ◽

Acid Etching ◽

Synthesis Methods ◽

Two Dimensional ◽

Energy Materials ◽

The Relationship

The unique properties of two-dimensional (2D) materials make them increasingly attractive in various fields, especially for energy harvesting, conversion, or storage. Simultaneously, numerous synthetic methods have been rapidly developed. Recently, topochemical strategies were demonstrated, and they show tremendous promising potential for synthesizing 2D materials due to their simplicity, scalability, and high efficiency. Considering the suitability of material structures and their synthesis methods, as well as the relationship between material properties and applications, it is necessary for researchers to comprehensively review and determine the prospects of 2D materials based on topological chemical synthesis methods and their related applications. Therefore, in this review, we systematically summarize and analyze the representative topochemical strategies for synthesizing 2D materials, including salt-templating methods for non-layered 2D materials, molten Lewis acid etching strategy for novel MXenes, and the chalcogen vapors etching and substituting strategy for phase-controlled 2D materials and so on, with the application of these 2D materials in energy-related fields including batteries, supercapacitors, and electrocatalysis. At the end of the paper, the corresponding perspective was also illustrated, and we expect that this could provide a reference for the future research in the field.

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Preparation of High-Purity Ammonium Tetrakis(pentafluorophenyl)borate for the Activation of Olefin Polymerization Catalysts

Molecules ◽

10.3390/molecules26092827 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2827

Author(s):

Hyun-Ju Lee ◽

Jun-Won Baek ◽

Yeong-Hyun Seo ◽

Hong-Cheol Lee ◽

Sun-Mi Jeong ◽

...

Keyword(s):

Type Species ◽

Olefin Polymerization ◽

Bulk Polymerization ◽

Aliphatic Hydrocarbon ◽

Polymerization Catalysts ◽

Co Catalyst ◽

Co Catalysts ◽

Hydrocarbon Solvents ◽

In Situ Activation

Homogeneous olefin polymerization catalysts are activated in situ with a co-catalyst ([PhN(Me)2-H]+[B(C6F5)4]− or [Ph3C]+[B(C6F5)4]−) in bulk polymerization media. These co-catalysts are insoluble in hydrocarbon solvents, requiring excess co-catalyst (>3 eq). Feeding the activated species as a solution in an aliphatic hydrocarbon solvent may be advantageous over the in situ activation method. In this study, highly pure and soluble ammonium tetrakis(pentafluorophenyl)borates ([Me(C18H37)2N-H]+[B(C6F5)4]− and [(C18H37)2NH2]+[B(C6F5)4]−) containing neither water nor Cl− salt impurities were prepared easily via the acid–base reaction of [PhN(Me)2-H]+[B(C6F5)4]− and the corresponding amine. Using the prepared ammonium salts, the activation reactions of commercial-process-relevant metallocene (rac-[ethylenebis(tetrahydroindenyl)]Zr(Me)2 (1-ZrMe2), [Ph2C(Cp)(3,6-tBu2Flu)]Hf(Me)2 (3-HfMe2), [Ph2C(Cp)(2,7-tBu2Flu)]Hf(Me)2 (4-HfMe2)) and half-metallocene complexes ([(h5-Me4C5)Si(Me)2(k-NtBu)]Ti(Me)2 (5-TiMe2), [(h5-Me4C5)(C9H9(k-N))]Ti(Me)2 (6-TiMe2), and [(h5-Me3C7H1S)(C10H11(k-N))]Ti(Me)2 (7-TiMe2)) were monitored in C6D12 with 1H NMR spectroscopy. Stable [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]− species were cleanly generated from 1-ZrMe2, 3-HfMe2, and 4-HfMe2, while the species types generated from 5-TiMe2, 6-TiMe2, and 7-TiMe2 were unstable for subsequent transformation to other species (presumably, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-type species). [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species were also prepared from 5-TiCl(Me) and 6-TiCl(Me), which were newly prepared in this study. The prepared [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]−-, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-, and [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species, which are soluble and stable in aliphatic hydrocarbon solvents, were highly active in ethylene/1-octene copolymerization performed in aliphatic hydrocarbon solvents.

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A Review on Synthesis Methods of Phyllosilicate- and Graphene-Filled Composite Hydrogels

Journal of Composites Science ◽

10.3390/jcs6010015 ◽

2022 ◽

Vol 6 (1) ◽

pp. 15

Author(s):

Sayan Ganguly ◽

Shlomo Margel

Keyword(s):

Physical Properties ◽

Water Uptake ◽

Electrostatic Interactions ◽

Supramolecular Assembly ◽

Synthetic Methods ◽

Van Der Waals Interactions ◽

Synthesis Methods ◽

Physical And Chemical ◽

Filled Composite

This review discusses, in brief, the various synthetic methods of two widely-used nanofillers; phyllosilicate and graphene. Both are 2D fillers introduced into hydrogel matrices to achieve mechanical robustness and water uptake behavior. Both the fillers are inserted by physical and chemical gelation methods where most of the chemical gelation, i.e., covalent approaches, results in better physical properties compared to their physical gels. Physical gels occur due to supramolecular assembly, van der Waals interactions, electrostatic interactions, hydrophobic associations, and H-bonding. For chemical gelation, in situ radical triggered gelation mostly occurs.

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In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083035 ◽

1978 ◽

Vol 36 (2) ◽

pp. 434-435

Author(s):

D. Reis ◽

B. Vian ◽

J. C. Roland

Keyword(s):

Cell Wall ◽

Self Assembly ◽

Plant Cell Wall ◽

Higher Plants ◽

Three Dimensional ◽

Cytochemical Study ◽

Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

10.26434/chemrxiv.7098695 ◽

2018 ◽

Author(s):

Elaine A. Kelly ◽

Judith E. Houston ◽

Rachel Evans

Keyword(s):

Real Time ◽

Absorption Spectroscopy ◽

Self Assembly ◽

Uv Light ◽

Wormlike Micelles ◽

Tetraethylene Glycol ◽

Light Illumination ◽

First Time ◽

Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such asdrug delivery and micellar catalysis. Currently, their behaviour in the equilibrium cis-and trans-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C8AzoOC8E4) using small-angle neutron scattering (SANS). We show that the incorporation of in-situUV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C8AzoOC8E4could switch between wormlike micelles (transnative state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked in-situthrough combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

10.26434/chemrxiv.9876395.v1 ◽

2019 ◽

Author(s):

Hao Wu ◽

Jeffrey Ting ◽

Siqi Meng ◽

Matthew Tirrell

Keyword(s):

Small Angle ◽

Self Assembly ◽

Electrostatic Interactions ◽

Polyelectrolyte Complex ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Kinetics Of ◽

Ray Scattering

We have directly observed the in situ self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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A Case Study: Analysis of Patents of Coronaviruses and Covid-19 for Technology Assesment and Future Research

Current Pharmaceutical Design ◽

10.2174/1381612826666200720233947 ◽

2020 ◽

Vol 26 ◽

Cited By ~ 1

Author(s):

Pankaj Musyuni ◽

Geeta Aggarwal ◽

Manju Nagpal ◽

Ramesh K. Goyal

Keyword(s):

Disease Management ◽

Research And Development ◽

Technological Development ◽

Research Work ◽

Large Family ◽

Future Research ◽

Biological Drugs ◽

Ongoing Research ◽

Patent Literature ◽

Patent Documents

Background: Protecting intellectual property rights are important and particularly pertinent for inventions which are an outcome of rigorous research and development. While the grant of patents is subject to establishing novelty and inventive step, it further indicates the technological development and helpful for researchers working in the same technical domain. The aim of the present research work is to map the existing work through analysis of patent literature, in the field of Coronaviruses (CoV), particularly COVID-19 (2019-nCoV). CoV is a large family of viruses known to cause illness in human and animals, particularly known for causing respiratory infections as evidenced in earlier times such as in MERS i.e. Middle East Respiratory Syndrome; SRS i.e. Severe Acute Respiratory Syndrome. A recently identified novel-coronavirus has known as COVID-19 which has currently caused pandemic situation across the globe. Objective: To expand analysis of patents related to CoV and 2019-nCoV. Evaluation has been conducted by patenting trends of particular strains of identified CoV diseases by present legal status, main concerned countries via earliest priority years and its assignee types and inventors of identified relevant patents. We analyzed the global patent documents to check the scope of claims along with focuses and trends of the published patent documents for the entire CoV family including 2019- nCoV through the present landscape. Methods: To extract the results, Derwent Innovation database is used by a combination of different key-strings. Approximately 3800 patents were obtained and further scrutinized and analyzed. The present write-up also discusses the recent progress of patent applications in a period of the year 2010 to 2020 (present) along with the recent developments in India for the treatment options for CoV and 2019-nCoV. Results: Present analysis showed that key areas of the inventions have been focused on vaccines and diagnostic kits apart from the composition for treatment of CoV. We also observed that no specific vaccine treatments is available for treatment of 2019-nCov, however, developing novel chemical or biological drugs and kits for early diagnosis, prevention and disease management is the primarily governing topic among the patented inventions. The present study also indicates potential research opportunities for the future, particularly to combat 2019-nCoV. Conclusion: The present paper analyzes the existing patents in the field of Coronaviruses and 2019-nCoV and suggests a way forward for the effective contribution in this upcoming research area. From the trend analysis, it was observed an increase in filing of the overall trend of patent families for a period of 2010 to the current year. This multifaceted analysis of identified patent literature provides an understanding of the focuses on present ongoing research and grey area in terms of the trends of technological innovations in disease management in patients with CoV and 2019-nCoV. Further, the findings and outcome of the present study offer insights for the proposed research and innovation opportunities and provide actionable information in order to facilitate policymakers, academia, research driven institutes and also investors to make better decisions regarding programmed steps for research and development for the diagnosis, treatment and taking preventive measures for CoV and 2019-nCoV. The present article also emphasizes on the need for future development and the role of academia and collaboration with industry for speedy research with a rationale.

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