scholarly journals Graphene Oxyhydride Catalysts in View of Spin Radical Chemistry

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 565
Author(s):  
Elena F. Sheka
Keyword(s):  
Active Sites ◽  
Basic Structure ◽  
Chemical Activity ◽  
Radical Chemistry ◽  
Spin Chemistry ◽  
Edge Part ◽  
Stable Radicals ◽  
Molecular Catalysts

This article discusses carbocatalysis that are provided with amorphous carbons. The discussion is conducted from the standpoint of the spin chemistry of graphene molecules, in the framework of which the amorphous carbocatalysts are a conglomerate of graphene-oxynitrothiohydride stable radicals presenting the basic structure units (BSUs) of the species. The chemical activity of the BSUs atoms is reliably determined computationally, which allows mapping the distribution of active sites in these molecular catalysts. The presented maps reliably show the BSUs radicalization provided with carbon atoms only, the nonterminated edge part of which presents a set of active sites. Spin mapping of carbocatalysts active sites is suggested as the first step towards the spin carbocatalysis of the species.

The 2003 CSC Pure or Applied Inorganic Chemistry Award Lecture Adventures in stable radical chemistry

2004 ◽  
Vol 82 (7) ◽  
pp. 1119-1127 ◽  
Author(s):  
Robin G Hicks
Keyword(s):  
Inorganic Chemistry ◽  
Materials Science ◽  
Polymer Synthesis ◽  
Stable Radical ◽  
Molecular Magnetism ◽  
Fundamental Interest ◽  
Radical Chemistry ◽  
Wide Range ◽  
Directed Synthesis ◽  
Stable Radicals

Stable radicals are of intense fundamental interest because they challenge conventional bonding paradigms, and they find a wide range of uses ranging from organic and polymer synthesis to biological and medicinal applications to materials science. Yet the directed synthesis and study of stable radicals for either fundamental or applied purposes are rarely pursued strategies. This Award Lecture describes my research group's efforts in exploratory and targeted research focusing on stable radical design.Key words: stable radicals, verdazyls, molecular magnetism.

scholarly journals Hybrid organic–inorganic structured materials as single-site heterogeneous catalysts

2012 ◽  
Vol 468 (2143) ◽  
pp. 1927-1954 ◽  
Author(s):  
Urbano Díaz ◽  
Mercedes Boronat ◽  
Avelino Corma
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Structural Characteristics ◽  
Inorganic Materials ◽  
Single Site ◽  
Structured Materials ◽  
Solid Catalysts ◽  
Highly Active ◽  
Molecular Catalysts ◽  
Inorganic Structure

Catalyst selectivity is associated with well-defined homogeneous active sites. Transition metal complexes and organocatalysts are highly active and selective in the homogeneous phase, and their heterogenization by incorporating them into inorganic solid materials allows combining their excellent catalytic activity with improved separation, recovering and recycling properties. In this article, we present the structural characteristics and catalytic properties of hybrid organic–inorganic materials in which the molecular catalysts are part of the inorganic structure, emphasizing the possibilities of periodic mesoporous hybrid materials and coordination polymers as single-site solid catalysts.

scholarly journals Effective Adsorption of Nutrients from Simulated Domestic Sewage by Modified Maifanite

2021 ◽  
Author(s):  
Zisen Liu ◽  
Yilingyun Zou ◽  
Yunli Liu ◽  
Feng Luo ◽  
Rou Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Nitrate Nitrogen ◽  
Oxygen Demand ◽  
Basic Structure ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Sulfuric Acid Treatment ◽  
Eutrophic Water ◽  
Nutrient Salt ◽  
Adsorption Rates

Abstract Modified maifanite (MMF) was prepared by synthesized method with sulfuric acid treatment and high temperature calcination, and evaluated as an effective adsorption material to remove the nutrient salt in waste watery. Compared with the raw maifanite (RMF), the MMF exhibited the higher adsorption capacity and higher removal efficiency. The results showed that the adsorption rates of total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH3-N), nitrate nitrogen (NOx-N) and Chemical Oxygen Demand (COD) by MMF (RMF) were86.7% (76.7%), 44.9% (34.5%), 29.1% (20.8%) and 79.8% (13.0%) respectively at 20 ℃ for 24 h. MMF kept the basic structure and composition of maifanite with stronger surface roughness and more adsorption active sites. This study suggests that MMF can be further applied to treat domestic sewage and eutrophic water.

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.

Scanning luminescence x-ray microscopy: Progress toward selective staining using microspheres

1994 ◽  
Vol 52 ◽  
pp. 74-75
Author(s):  
C. Jacobsen ◽  
J. Fu ◽  
S. Mayer ◽  
Y. Wang ◽  
S. Williams
Keyword(s):  
Visible Light ◽  
Active Sites ◽  
Light Emission ◽  
Chinese Hamster ◽  
Polystyrene Spheres ◽  
Good Resistance ◽  
X Ray ◽  
Selective Staining ◽  
Visible Light Emission ◽  
Specific Labelling

In scanning luminescence x-ray microscopy (SLXM), a high resolution x-ray probe is used to excite visible light emission (see Figs. 1 and 2). The technique has been developed with a goal of localizing dye-tagged biochemically active sites and structures at 50 nm resolution in thick, hydrated biological specimens. Following our initial efforts, Moronne et al. have begun to develop probes based on biotinylated terbium; we report here our progress towards using microspheres for tagging.Our initial experiments with microspheres were based on commercially-available carboxyl latex spheres which emitted ~ 5 visible light photons per x-ray absorbed, and which showed good resistance to bleaching under x-ray irradiation. Other work (such as that by Guo et al.) has shown that such spheres can be used for a variety of specific labelling applications. Our first efforts have been aimed at labelling ƒ actin in Chinese hamster ovarian (CHO) cells. By using a detergent/fixative protocol to load spheres into cells with permeabilized membranes and preserved morphology, we have succeeded in using commercial dye-loaded, spreptavidin-coated 0.03μm polystyrene spheres linked to biotin phalloidon to label f actin (see Fig. 3).

Microstructure and crystal symmetry of Pb2Sr2(Y/Ca)Cu3O9−δ

1990 ◽  
Vol 48 (4) ◽  
pp. 64-65
Author(s):  
Y. P. Lin ◽  
J. S. Xue ◽  
J. E. Greedan
Keyword(s):  
Electron Diffraction ◽  
High Temperature Superconductors ◽  
Carbon Film ◽  
Basic Structure ◽  
Crystal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
New Family ◽  
Convergent Beam

A new family of high temperature superconductors based on Pb2Sr2YCu3O9−δ has recently been reported. One method of improving Tc has been to replace Y partially with Ca. Although the basic structure of this type of superconductors is known, the detailed structure is still unclear, and various space groups has been proposed. In our work, crystals of Pb2Sr2YCu3O9−δ with dimensions up to 1 × 1 × 0.25.mm and with Tc of 84 K have been grown and their superconducting properties described. The defects and crystal symmetry have been investigated using electron microscopy performed on crushed crystals supported on a holey carbon film.Electron diffraction confirmed x-ray diffraction results which showed that the crystals are primitive orthorhombic with a=0.5383, b=0.5423 and c=1.5765 nm. Convergent Beam Electron Diffraction (CBED) patterns for the and axes are shown in Figs. 1 and 2 respectively.

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