Nanocomposites Based Upon Alumina and Zirconia Pillared Clays Loaded with Transition Metal Cations and Clusters of Precious Metals: Synthesis, Properties and Catalysis of NOx Selective Reduction by Hydrocarbons

1999 ◽  
Vol 581 ◽  
Author(s):  
Vladislav A. Sadykov ◽  
R. V. Bunina ◽  
G. M. Alikina ◽  
V. P. Doronin ◽  
T. P. Sorokina ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Nitrogen Oxides ◽  
Transition Metal ◽  
Catalytic Properties ◽  
Precious Metals ◽  
Selective Reduction ◽  
Pillared Clays ◽  
Active Components ◽  
Synthesis Properties ◽  
Nitrogen Oxides Reduction

ABSTRACTThermally stable alumina and zirconia pillared clays loaded with copper and cobalt cations and silver nanoparticles were synthesized. The structural and surface features of these nanosystems were studied and compared with those of bulk analogs -partially stabilized zirconias and γ-alumina loaded with the same active components. Specificity of the catalytic properties of nanocomposites in the reactions of nitrogen oxides reduction by propane, propylene and decane in the excess of oxygen appears to be determined both by the degree of interaction between pillars and active components and the type of reducing agent.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Single-Step Green Synthesis of Highly Concentrated and Stable Colloidal Dispersion of Core-Shell Silver Nanoparticles and Their Antimicrobial and Ultra-High Catalytic Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1007
Author(s):  
Azam Ali ◽  
Mariyam Sattar ◽  
Fiaz Hussain ◽  
Muhammad Humble Khalid Tareen ◽  
Jiri Militky ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Tannic Acid ◽  
Rate Constant ◽  
Catalytic Properties ◽  
Colloidal Dispersion ◽  
Alkaline Condition ◽  
Core Shell ◽  
Average Particle ◽  
Ag Nps

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of silver nanoparticles (Ag NPs) was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized Ag NPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) Ag NPs, capped with poly-tannic acid (Ag NPs-PTA). The average particle size of Ag NPs-PTA was found to be 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed to be stable for more than 15 months in the ambient environment (25 °C, 65% relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus (ZOI 3.0 mM) and Escherichia coli (ZOI 3.5 mM). Ag NPs-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s−1·mg−1. For comparison, bare Ag NPs show catalytic activity with a normalized rate constant of 139.78 mL·s−1·mg−1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The ultra-high catalytic and good antimicrobial properties can be attributed to the fine size and good aqueous stability of Ag NPs-PTA. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and medical.

scholarly journals Recent Advances in the Use of Transition-Metal Porphyrin and Phthalocyanine Complexes as Electro-Catalyst Materials on Modified Electrodes for Electroanalytical Sensing Applications

Solids ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 212-231
Author(s):  
J. Antonio Cruz-Navarro ◽  
Fabiola Hernández-García ◽  
Luis Humberto Mendoza-Huizar ◽  
Verónica Salazar-Pereda ◽  
J. Ángel Cobos-Murcia ◽  
...  
Keyword(s):  
Transition Metal ◽  
Catalytic Properties ◽  
Modified Electrodes ◽  
Metal Porphyrin ◽  
Water Contaminants ◽  
Active Behavior ◽  
Sensing Applications ◽  
Redox Active ◽  
Innovative Materials ◽  
Solid Electrodes

Metalloporphyrins (MP) and metallophtalocyanines (MPc) are innovative materials with catalytic properties that have attracted attention for their application for diverse electrochemical purposes. The presence of metallic centers in their structure offers a redox-active behavior that is being applied in the design of solid electrodes for the quantification of biomolecules, water contaminants, and pharmaceuticals, among others. Herein, we collect the recent information about porphyrin and phthalocyanine complexes as modifiers of electrodes, and the important aspects of the design, characterization, and application of these electrodes.

Enhanced magneto-optical and photo-catalytic properties of transition metal cobalt (Co2+ ions) doped spinel MgFe2O4 ferrite nanocomposites

2018 ◽  
Vol 452 ◽  
pp. 380-388 ◽  
Author(s):  
A. Godlyn Abraham ◽  
A. Manikandan ◽  
E. Manikandan ◽  
S. Vadivel ◽  
S.K. Jaganathan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Catalytic Properties

Development of silica-supported frustrated Lewis pairs: highly active transition metal-free catalysts for the Z-selective reduction of alkynes

2016 ◽  
Vol 6 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Kai C. Szeto ◽  
Wissam Sahyoun ◽  
Nicolas Merle ◽  
Jessica Llop Castelbou ◽  
Nicolas Popoff ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Selective Reduction ◽  
Frustrated Lewis Pairs ◽  
Acid Base ◽  
Metal Free ◽  
Highly Active ◽  
Active Transition ◽  
Lewis Pairs

Supported Lewis acid/base systems based have been prepared and characterized.

Comparison of catalytic properties of NiMoAl2O3 with NiMo supported on Al-, Ti-pillared clays in HDS of residual oils

1997 ◽  
Vol 150 (1) ◽  
pp. 37-52 ◽  
Author(s):  
C.E. Ramos-Galvan ◽  
G. Sandoval-Robles ◽  
A. Castillo-Mares ◽  
J.M. Dominguez
Keyword(s):  
Catalytic Properties ◽  
Pillared Clays

Exhaust nitrogen oxides reduction system (ExNORS)

2021 ◽  
pp. 36-38
Author(s):  
E. V. OVCHINNIKOV ◽  
S. Yu. UYUTOV ◽  
V. A. KRYUCHKOV
Keyword(s):  
Nitrogen Oxides ◽  
Reduction System ◽  
Nitrogen Oxides Reduction
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