Structure and catalytic activity of metal complexes on carriers 3. Rhodium complexes on modified polymers and their catalytic properties in the reduction of nitrobenzene by chemically bound hydrogen

1990 ◽  
Vol 39 (2) ◽  
pp. 217-221 ◽  
Author(s):  
V. F. Dovganyuk ◽  
V. Z. Sharf ◽  
V. K. Belyaeva ◽  
I. N. Marov ◽  
Zh. L. Dykh ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Complexes ◽  
Catalytic Properties ◽  
Rhodium Complexes ◽  
Modified Polymers

Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Nickel Oxide ◽  
Catalytic Properties ◽  
Cadmium Oxide ◽  
Chemisorb Oxygen ◽  
Composition Region ◽  
Chemisorbed Oxygen ◽  
Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

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 Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Major Influence ◽  
Pt Catalysts ◽  
Reduction Temperature ◽  
Metal Dispersion ◽  
Tungsten Oxides ◽  
Supported Pt Catalysts

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.

scholarly journals Synthesis of Hierarchical MOR-Type Zeolites with Improved Catalytic Properties

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4508
Author(s):  
Zeinab Mcheik ◽  
Ludovic Pinard ◽  
Joumana Toufaily ◽  
Tayssir Hamieh ◽  
T. Jean Daou
Keyword(s):  
Catalytic Activity ◽  
Amorphous Materials ◽  
Essential Role ◽  
Aluminum Content ◽  
Catalytic Properties ◽  
Hexadecyltrimethylammonium Bromide ◽  
Zeolite Framework ◽  
Ctab Concentration ◽  
Porous Volume ◽  
Synthesis Medium

Hierarchical MOR-type zeolites were synthesized in the presence of hexadecyltrimethylammonium bromide (CTAB) as a porogen agent. XRD proved that the concentration of CTAB in the synthesis medium plays an essential role in forming pure hierarchical MOR-type material. Above a CTAB concentration of 0.04 mol·L−1, amorphous materials are observed. These hierarchical mordenite possess a higher porous volume compared to its counterpart conventional micrometer crystals. Nitrogen sorption showed the presence of mesoporosity for all mordenite samples synthesized in the presence of CTAB. The creation of mesopores due to the presence of CTAB in the synthesis medium does not occur at the expense of zeolite micropores. In addition, mesoporous volume and BET surface seem to increase upon the increase of CTAB concentration in the synthesis medium. The Si/Al ratio of the zeolite framework can be increased from 5.5 to 9.1 by halving the aluminum content present in the synthesis gel. These synthesized hierarchical MOR-type zeolites possess an improved catalytic activity for n-hexane cracking compared to large zeolite crystals obtained in the absence of CTAB.

Synthesis of heteroleptic phosphine–copper(i) complexes: fluorescence sensing and catalytic properties

2021 ◽  
Author(s):  
Chen-Lin Luo ◽  
Chu-Xing Hu ◽  
Ping Shang ◽  
Guan-Zhao Wen ◽  
Jia-Jun Zhu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Properties ◽  
Silver Ions ◽  
High Catalytic Activity ◽  
Diphosphine Ligands ◽  
Fluorescence Sensing ◽  
Cuaac Reaction

A series of heteroleptic Cu(i) complexes were precisely synthesized using different bipyridine and diphosphine ligands. These complexes exhibited fluorescence sensing towards silver ions and high catalytic activity towards the CuAAC reaction.

Metal complexes of tetrakis(2-carboxyphenylsulfanyl)phthalocyanine. Synthesis, spectral and catalytic properties

2021 ◽  
Vol 70 (7) ◽  
pp. 1297-1303
Author(s):  
A. A. Botnar’ ◽  
N. P. Domareva ◽  
D. A. Erzunov ◽  
N. A. Futerman ◽  
T. V. Tikhomirova ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Catalytic Properties

A monovacant heteropolytungstate-incorporated trimeric carbonyl rhenium cluster, [(AsW11O39){Re(CO)3}3(μ3-OH)(μ2-OH)]6−: synthesis, structure and catalytic properties

RSC Advances ◽  
2014 ◽  
Vol 4 (55) ◽  
pp. 28848-28851 ◽  
Author(s):  
Yanhui Zhang ◽  
Dongdi Zhang ◽  
Zhiyuan Huo ◽  
Pengtao Ma ◽  
Jingyang Niu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Selectivity ◽  
Catalytic Properties ◽  
The Novel ◽  
Rhenium Cluster

The novel undecatungstoarsenate-supported carbonyl rhenium derivative exhibits prominent catalytic activity and high selectivity in the cycloaddition of epoxides.

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