scholarly journals Realistic Modelling of Dynamics at Nanostructured Interfaces Relevant to Heterogeneous Catalysis

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Kevin Rossi ◽  
Tzonka Mineva ◽  
Jean-Sebastien Filhol ◽  
Frederik Tielens ◽  
Hazar Guesmi
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalyst Surface ◽  
State Of The Art ◽  
Short Review ◽  
Metal Catalyst ◽  
Reaction Conditions ◽  
Know How ◽  
Liquid Adsorption ◽  
Metal Support ◽  
Nanostructured Interfaces

The focus of this short review is directed towards investigations of the dynamics of nanostructured metallic heterogeneous catalysts and the evolution of interfaces during reaction—namely, the metal–gas, metal–liquid, and metal–support interfaces. Indeed, it is of considerable interest to know how a metal catalyst surface responds to gas or liquid adsorption under reaction conditions, and how its structure and catalytic properties evolve as a function of its interaction with the support. This short review aims to offer the reader a birds-eye view of state-of-the-art methods that enable more realistic simulation of dynamical phenomena at nanostructured interfaces by exploiting resource-efficient methods and/or the development of computational hardware and software.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

scholarly journals Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1680
Author(s):  
Marta A. Andrade ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Oxygen Species ◽  
Styrene Oxidation ◽  
Reaction Conditions ◽  
Reactive Metal ◽  
Catalytic Systems ◽  
Tert Butyl Hydroperoxide ◽  
Metal Organic ◽  
Important Intermediate

The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal–organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal–oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.

scholarly journals Cholinium amino acid-based ionic liquids

2021 ◽  
Author(s):  
Andrea Le Donne ◽  
Enrico Bodo
Keyword(s):  
Ionic Liquids ◽  
Amino Acid ◽  
Computational Chemistry ◽  
Special Class ◽  
State Of The Art ◽  
Short Review ◽  
Research Activity ◽  
Intensive Research ◽  
Low Toxicity ◽  
Molecular Components

AbstractBoosted by the simplicity of their synthesis and low toxicity, cholinium and amino acid-based ionic liquids have attracted the attention of researchers in many different fields ranging from computational chemistry to electrochemistry and medicine. Among the uncountable IL variations, these substances occupy a space on their own due to their exceptional biocompatibility that stems from being entirely made by metabolic molecular components. These substances have undergone a rather intensive research activity because of the possibility of using them as greener replacements for traditional ionic liquids. We present here a short review in the attempt to provide a compendium of the state-of-the-art scientific research about this special class of ionic liquids based on the combination of amino acid anions and cholinium cations.

scholarly journals Intraoperative ultrasound in robot-assisted partial nephrectomy: State of the art

2018 ◽  
Vol 90 (3) ◽  
pp. 195-198 ◽  
Author(s):  
Giacomo Di Cosmo ◽  
Enrica Verzotti ◽  
Tommaso Silvestri ◽  
Andrea Lissiani ◽  
Roberto Knez ◽  
...  
Keyword(s):  
Partial Nephrectomy ◽  
State Of The Art ◽  
Short Review ◽  
Robot Assisted ◽  
Small Renal Masses ◽  
Renal Masses ◽  
Ischemia Time ◽  
Oncological Safety ◽  
Nephron Sparing ◽  
Operative Ultrasound

Introduction: Nephron-sparing surgery (NSS) is of one of the most studied fields in urology due to the balancing between renal function preservation and oncological safety of the procedure. Aim of this short review is to report the state of the art of intra-operative ultrasound as an operative tool to improve localization of small renal masses partially or completely endophytic during robotassisted partial nephrectomy (RAPN). Material and methods: We performed a literature review by electronic database on Pubmed about the use of intra-operative US in RAPN to evaluate the usefulness and the feasibility of this procedure. Results: Several studies analyzed the use of different US probes during RAPN. Among them some focused on using contrastenhanced ultra sonography (CEUS) for improving the dynamic evaluation of microvascular structure allowing the reduction of ischemia time (IT). We reported that nowaday the use of intraoperative US during RAPN could be helpful to improve the preservation of renal tissue without compromising oncological safety. Moreover, during RAPN there is no need for assistant to hand the US probe increasing surgeon autonomy. Conclusions: The use of a robotic ultrasound probe during partial nephrectomy allows the surgeon to optimize tumor identification with maximal autonomy, and to benefit from the precision and articulation of the robotic instrument during this key step of the partial nephrectomy procedure. Moreover US could be useful to reduce ischemia time (IT). The advantages of nephron-sparing surgery over radical nephrectomy is well established with a pool of data providing strong evidence of oncological and survival equivalency. With the progressive growth of robot-assisted partial nephrectomy (RAPN) techniques, the use of several tools has been progressively developed to help the surgeon in the identification of masses and its vascular net. In this short review we tried to analyze the current use of intra-operative ultrasound as an operative tool to improve localization of small renal masses partially or completely endophytic during RAPN.

scholarly journals Kertsopoulos Innovation: The Three Multi-plane Polarities and the Three Interactions and Schematic Representations in the Sense of the General Cause of the Dynamic Difference

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Magnetic Fields ◽  
Magnetic System ◽  
State Of The Art ◽  
Magnetic Devices ◽  
Know How ◽  
Patented Invention ◽  
Scientific Laws ◽  
First Time ◽  
Multiple Interactions

As it is known: in the state of the art, the like and the unlike polarity between two magnets remains independent of the distance between them. According to the invention: “Magnetic System of Three Interactions”, International office of patents WIPO-PCT, bearing the No WO/2013/136097of the inventor Georgios K. Kertsopoulos, the like and the unlike polarity between two magnetic constructions depends on the distance between them [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]. The know-how of the invention makes it possible for interacting magnetic constructions to possess and perform interchangeable more than 96 polarities and interactions. Polarities and magnetic fields can in multiple ways interchange, depending on the varying distance between two interacting confronted magnetic constructions, offering many new variable design capabilities. For the first time, new types of poles are created, for example: simultaneous like-unlike poles or simultaneous unlike-like poles are created, causing stable or unstable balance as an interaction; also, for the first time in magnetism, new types of magnetic fields are formed never before observed, for example: remote fields of very strong attraction, without however, the contact of the magnetic constructions. The magnetic devices that perform these multiple interactions are fully patented internationally, published in a book in English, by the inventor a book in English, by the inventor [11]. The new scientific laws and principles, revealed through these experiments enrich the very basics, the foundation of magnetism, since many new types of polarities and interactions are introduced and are made possible for the first time in science and technology. In figure 1 of the article we observe the division and determination of the empty air space, between the magnetic constructions, at three distances and two boundaries which apply both for the like and the unlike front poles and in figure 2 we observe the three typical spatial distances, the three multi-plane polarities and the three interactions with properties and with spatial boundaries and interactions based on the bundles of the dynamic lines between the two magnetic constructions, on the guide, when the poles of the front poles of the arrangements are initially like. Furthermore, in figure 7 we observe a schematic representation of the three different fields (175), (177) and (178) between the above-mentioned magnetic arrangements of the constructions of the invention, with initially like front poles, in the sense of the general cause of the dynamic difference. This article is in continuation of the following published article that introduces the reader to the invention’s technology: Georgios K. Kertsopoulos (2018) Innovation article: 36 over passed restrictions of magnetism achieved by the 96 multiple magnetic polarities-interactions performed by the Kertsopoulos world patented invention vs. the known two. Advances in Nanoscience and nanotechnology [12]. https://www.opastonline.com/wp-content/uploads/2018/12/36-over-passed-restrictions-of-magnetism-achieved-by-the-96- multiple-magnetic-polarities-interactions-performed-by-the-kertsopoulos-world-ann-18.pdf?fbclid=IwAR1jYPFME5mhX2FLbKKTPAdu0YMe3FqHtoUdoRoeao8mKIp1GRuWeovEaA

scholarly journals Synthesis and characterization of Mo2 C based materials over activated carbon derived from sewage sludge pyrolysis for catalytic applications

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 148-155
Author(s):  
A. C. Alexandrino ◽  
J. F. de Sousa ◽  
C. P. de Souza ◽  
C. P. B. de Araújo ◽  
M. V. M. Souto
Keyword(s):  
Sewage Sludge ◽  
Surface Area ◽  
Synthesis Method ◽  
Metal Catalyst ◽  
Catalytic Material ◽  
Metal Support ◽  
Size Evaluation ◽  
Adsorption Desorption ◽  
Substitute Materials

Abstract Transition metal carbides have been successfully used as substitute materials for conventional noble metal catalyst in several important industrial reactions due to their interesting physicochemical properties. Surface structure, chemical composition and metal-support interactions, as well as processing conditions, are of utmost importance in the use of such materials in catalysis. The present study aimed to synthesize and evaluate pure molybdenum carbide with and without support, and bimetallic Mo-Ni carbide over a carbon active support derived from sewage sludge pyrolysis. The support was chemically (KOH) and physically (thermal treatment) activated before use. TG/DTG, XRD, XRF, SEM, BET and particle size evaluation were performed, together with adsorption/desorption isotherms. Results indicated that the applied synthesis method was adequate for the obtainment of pure materials. The increase in surface area of the support was significant, from 13 to 141 m².g-1 after the thermal and chemical treatment; also, supporting Mo2C over carbon provided an increase from 45 to 73 m².g-1 in surface area, which indicated its potential as a catalytic material as well as the effectiveness of the applied methodology.

Five-Membered Hetarene N-Oxides: Recent Advances in Synthesis and Reactivity

Synthesis ◽  
2021 ◽  
Author(s):  
Leonid Fershtat ◽  
Fedor Teslenko
Keyword(s):  
Transition Metal ◽  
Medicinal Chemistry ◽  
Materials Science ◽  
State Of The Art ◽  
Short Review ◽  
Advanced Materials ◽  
Metal Free ◽  
Recent Advances ◽  
Application Potential ◽  
Metal Catalyzed

Five-membered heterocyclic N-oxides attracted special attention due to their strong application potential in medicinal chemistry and advanced materials science. In this regard, novel methods for their synthesis and functionalization are constantly required. In this short review, recent state-of-the-art achievements in the chemistry of isoxazoline N-oxides, 1,2,3-triazole 1-oxides and 1,2,5-oxadiazole 2-oxides are briefly summarized. Main routes to transition-metal-catalyzed and metal-free functionalization protocols along with mechanistic considerations are outlined. Transformation patterns of the hetarene N-oxide rings as precursors to other nitrogen heterocyclic systems are also presented.

Novel heterogeneous catalysts in the wet peroxide oxidation of phenol

2001 ◽  
Vol 44 (5) ◽  
pp. 153-160 ◽  
Author(s):  
G. Ovejero ◽  
J.L. Sotelo ◽  
F. Martínez ◽  
L. Gordo
Keyword(s):  
Heterogeneous Catalysts ◽  
Mixed Oxides ◽  
Isomorphous Substitution ◽  
Phenol Removal ◽  
Metallic Ions ◽  
Peroxide Oxidation ◽  
Reaction Conditions ◽  
Wet Peroxide Oxidation ◽  
Cu Catalysts ◽  
Zeolitic Materials

Catalytic wet peroxide oxidation (CWPO) of diluted aqueous solutions of phenol has been studied over a series of heterogeneous catalysts at 100°C under 1MPa air pressure. Several catalysts were prepared and tested including zeolitic materials exchanged with metallic ions such as Fe and Cu and different mixed oxides. Likewise, a Fe-TS- zeolite was synthesised by isomorphous substitution of Si atoms by Fe and Ti into the MFI zeolitic framework through hydrothermal synthesis of wetness-impregnated Fe2O3-TiO2-SiO2 xerogels. This material showed a complete phenol removal and TOC reduction of up to 68% under the reaction conditions, with a low leaching of iron species as compared to Fe-exchanged zeolitic materials. Perovskite of type LaTi0.45Cu0.55O3 was also tested, showing copper leaching of 22%, with a TOC conversion of 93% and total phenol removal. The capacity of Fe and Cu containing catalysts to promote free radicals in the presence of H2O2 as well as the thermal decomposition of the oxidant under the reaction conditions have also been studied. In the absence of hydrogen peroxide, Fe and Cu catalysts were not effective in order to decrease TOC content.

scholarly journals A mini-review of TAT-MyoD fused proteins: state of the art and problems to solve

2017 ◽  
Vol 27 (4) ◽  
Author(s):  
Marco Patruno ◽  
Luca Melotti ◽  
Chiara Gomiero ◽  
Roberta Sacchetto ◽  
Ohad Topel ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Viral Replication ◽  
Cell Nucleus ◽  
State Of The Art ◽  
Transcriptional Activator ◽  
Short Review ◽  
Tat Protein ◽  
Small Peptide ◽  
Extracellular Milieu ◽  
Innovative Methodology

The transcriptional activator TAT is a small peptide essential for viral replication and possesses the property of entering the cells from the extracellular milieu, acting as a membrane shuttle. In order to safely differentiate cells an innovative methodology, based on the fusion of transcription factors and the TAT sequence, is discussed in this short review. In several studies, it has been demonstrated that TAT protein can be observed in the cell nucleus after few hours from the inoculation although its way of action is not fully understood. However, further studies will be necessary to develop this methodology for clinical purposes.

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