ChemInform Abstract: Supported Catalysts. Redox Methods for Preparation of Bimetallic Catalysts

ChemInform ◽  
2010 ◽  
Vol 31 (29) ◽  
pp. no-no
Author(s):  
J. Barbier
Keyword(s):  
Bimetallic Catalysts ◽  
Supported Catalysts

Zeolite Supported Bimetallic Catalyst System: The Effect of Metal Loading for Catalytic Pyrolysis of Jatropha Residue

2017 ◽  
Vol 751 ◽  
pp. 494-499
Author(s):  
Vituruch Goodwin ◽  
Phanwatsa Amnaphiang ◽  
Pimpreeya Thungngern ◽  
Kong Kah Shin ◽  
Parncheewa Udomsap ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Catalytic Pyrolysis ◽  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Acid Sites ◽  
One Step ◽  
Step Loading ◽  
Loading Sequence ◽  
Xrd Patterns ◽  
The One

Two transition metals were loaded on H-ZSM-5 zeolite to produce bimetallic zeolite supported catalysts for catalytic pyrolysis reaction. Ni and Co metal were loaded on H-ZSM-5 via wet impregnation method. The loading sequence was applied using one-step and two-step loading method. The different loading sequence affect surface properties of catalyst and catalytic activity in pyrolysis reaction. The bimetallic catalysts were prepared at Ni+Co metal loading content of 10+10 wt% (Ni:Co=1:1) to 10+20 wt% (Ni:Co=1:2 or 2:1). All bimetallic catalysts supported on H-ZSM-5 were calcined and characterized by X-ray Diffraction (XRD), Surface area analysis (BET) and Temperature Programmed Desorption of ammonia (NH3-TPD). The XRD patterns of bimetallic zeolite supported catalysts revealed that loading of two metals at high content affect crystalline structural of ZSM-5 support. All XRD patterns illustrated peaks characteristic of ZSM-5, cobalt oxide and nickel oxide. The NH3-TPD results showed number of acid sites of the catalyst which revealed that the acid sites of ZSM-5 support was weakened with transition metal added. The two-step loading of 10+20 wt% metals on ZSM-5 reduced the peak intensities of NH3 desorption due to the metal particles aggregate on acid sites of ZSM-5. The two-step 10+20 wt% bimetallic catalysts has the lowest surface acidity, followed by the one-step 10+20 wt%, the two-step 10+10 wt% and the one-step 10+10 wt% bimetallic catalysts, respectively. Jatropha residue was used for catalytic pyrolysis study. Jatropha residue and bimetallic catalyst was pyrolyzed at 500 °C in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The product vapor was analyzed by GC/MS for the different groups of organic products such as fatty acid, aldehydes, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and nitrogen compounds. The product from catalytic pyrolysis of jatropha residue with bimetallic zeolite supported catalysts enhance deoxygenation reaction that resulted in high aliphatic and aromatic hydrocarbons product. The one-step loading at ratio Ni:Co = 1:1 (10+10 wt%) gave the highest hydrocarbons product yield at 57.81%.

scholarly journals Synthesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

2009 ◽  
Vol 15 (4) ◽  
pp. 263-270 ◽  
Author(s):  
Sanja Ratkovic ◽  
Erne Kiss ◽  
Goran Boskovic
Keyword(s):  
Carbon Nanotubes ◽  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Chemical Vapor ◽  
Active Phase ◽  
Precipitation Method ◽  
High Yield ◽  
Chemical Vapor Deposition Method ◽  
Hydrogen Flow ◽  
Graphite Nanoparticles

Carbon nanotubes (CNTs) were synthesized by a catalytic chemical vapor deposition method (CCVD) of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 ?C and in situ reduced in hydrogen flow at 700?C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica-supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

scholarly journals Hydrogenation of Aromatic Nitrocompounds on Supported Mono- and Bimetallic Catalysts

2016 ◽  
Vol 2 (1) ◽  
pp. 101 ◽  
Author(s):  
A.T. Massenova ◽  
L.R. Sassykova
Keyword(s):  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Supported Catalysts ◽  
Bifunctional Catalysts ◽  
Adsorbed Hydrogen ◽  
Reaction Conditions ◽  
Pd Catalysts ◽  
Aromatic Nitrocompounds ◽  
Metal Metal ◽  
Optimal Reaction

<p>Catalytic hydrogenation of substituted aromatic nitrocompounds and hydrocarbons has been studied. It was established that monometallic Pd-catalysts were suitable for reduction of nitrogroups. Bifunctional catalysts such as Rh-Pt, Rh-Pd, Pd-Ru and Rh-Ru were used for hydrogenation of both aromatic ring and nitrogroup and sequence of their hydrogenation depended on support nature. Over Rh-Pt alumina supported catalysts consequent hydrogenation of NO<sub>2</sub> and benzene ring took place, over silica supported catalysts their consecutive hydrogenation was observed. Such catalytic properties of bimetallic Rh-Pt and Rh-Pd catalysts probably connected with metal-metal interaction leading to optimal adsorption strength of uniformly adsorbed hydrogen. The optimal reaction conditions (temperature and hydrogen pressure) have been elaborated for synthesis of alicyclic amines with 95-99% yields.</p>

Role of Energy Dissipation and Surface Mobility in Heterogeneous Catalysis by Metals

1998 ◽  
Vol 63 (11) ◽  
pp. 1851-1868 ◽  
Author(s):  
Zlatko Knor ◽  
Jan Plšek
Keyword(s):  
Energy Dissipation ◽  
Gas Phase ◽  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Bound State ◽  
Reaction Products ◽  
Atomic Steps ◽  
Surface Mobility ◽  
Species Mobility

The fundamental role of excess energy dissipation and of surface species mobility, both in the preparation of model metallic catalysts (bimetallic catalysts, bimetallic oxide-supported catalysts), and in the activation of reactant molecules on the catalyst surfaces (single crystals, bimetallic and bimetallic oxide-supported catalysts) are discussed. A generalized model of surface interactions is proposed which satisfactorily explains the trapping of particles from the gas phase at the atomic steps and recovery of the trapping sites due to migration of the trapped species towards flat terraces. Higher probability of encounter of these species with other reactants on flat terraces and easier desorption of the reaction products from there in comparison with the bound state at the edges of atomic steps can be expected. Results of FIM and FEM studies of Pt, Dy-W, Pd-W and Pd-Mo systems are used to illustrate selected features of the proposed general model.

Design of Bimetallic Catalysts: From Model Surfaces to Supported Catalysts

2009 ◽  
pp. 195-212 ◽  
Author(s):  
Jeffrey P. Bosco ◽  
Michael P. Humbert ◽  
Jingguang G. Chen
Keyword(s):  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Model Surfaces

scholarly journals CO2 Reforming of CH4 on Co-Containing Supported Catalysts

2016 ◽  
Vol 2 (1) ◽  
pp. 41 ◽  
Author(s):  
Sh.S. Itkulova ◽  
K.Z. Zhunusova ◽  
I.S. Chanycheva ◽  
G.D. Zakumbaeva
Keyword(s):  
Carbon Dioxide ◽  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Carbon Oxide ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Reaction Products ◽  
Co2 Reforming ◽  
Co2 Reforming Of Ch4

<p>Mono- and bimetallic cobalt-containing catalysts supported on alumina have been investigated in the reaction of interaction between carbon dioxide and methane at variation of experiment temperature and pressure. It was shown, that the bimetallic catalysts have a high activity in this reaction in compare with monometallic ones. The main reaction products are carbon oxide, hydrogen, water and oxygenates. The yield of latter reaches 30% at certain conditions (P &gt; 0.5 MPa, T &lt; 853K). The maximum conversion of both methane (100%) and carbon dioxide (94%) is reached at lower pressure (0.1MPa) and 1023 K. In these conditions the synthesis-gas is a main reaction product. One of the advantages of the bimetallic catalysts is their resistance to coke formation.</p>

Microstructure of supported platinum-gold bimetallic catalysts

1989 ◽  
Vol 47 ◽  
pp. 260-261
Author(s):  
Amit Sachdev
Keyword(s):  
Bimetallic Catalysts ◽  
Active Sites ◽  
Supported Catalysts ◽  
High Resolution Electron Microscopy ◽  
Electron Microscopic ◽  
Adsorption Sites ◽  
Small Probe ◽  
Resolution Electron ◽  
Partially Miscible ◽  
Microscopic Studies

Bimetallic supported catalysts comprised of a Group VIII metal, such as platinum, and a Group IB element, like gold, have been found to possess superior selectivities towards the formation of desired products as well as a decreased rate of deactivation. The correlation between the microstructure of these materials with their catalytic behavior is essential in understanding the reaction kinetics. Previous electron microscopic studies on bimetallic catalysts have primarily concentrated upon systems whose metallic components are immiscible in the bulk. In this project, the partially miscible Pt-Au and the completely miscible Pt-Sn systems were investigated. In Pt-Au catalysts the catalytically inactive Au component is known to dilute the ensembles of the Pt active sites, thereby favoring the production of compounds whose intermediates require fewer adsorption sites. The typical metal particle size distribution in Pt-Au catalysts ranges from 0.5 nm to 40 nm. The microanalysis of particles larger than 10 nm can be easily done by means of small probe microdiffraction and EDX. The structure and composition of the smaller particles, where most of the interesting catalysis takes place, was determined from the structure images of high resolution electron microscopy.

scholarly journals Bimetallic Catalysts for Volatile Organic Compound Oxidation

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 661
Author(s):  
Roberto Fiorenza
Keyword(s):  
Bimetallic Catalysts ◽  
Photocatalytic Oxidation ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Total Oxidation ◽  
Voc Removal ◽  
Bimetallic Systems ◽  
Volatile Organic ◽  
Potential Applications ◽  
Catalytic Stability

In recent years, the impending necessity to improve the quality of outdoor and indoor air has produced a constant increase of investigations in the methodologies to remove and/or to decrease the emission of volatile organic compounds (VOCs). Among the various strategies for VOC elimination, catalytic oxidation and recently photocatalytic oxidation are regarded as some of the most promising technologies for VOC total oxidation from urban and industrial waste streams. This work is focused on bimetallic supported catalysts, investigating systematically the progress and developments in the design of these materials. In particular, we highlight their advantages compared to those of their monometallic counterparts in terms of catalytic performance and physicochemical properties (catalytic stability and reusability). The formation of a synergistic effect between the two metals is the key feature of these particular catalysts. This review examines the state-of-the-art of a peculiar sector (the bimetallic systems) belonging to a wide area (i.e., the several catalysts used for VOC removal) with the aim to contribute to further increase the knowledge of the catalytic materials for VOC removal, stressing the promising potential applications of the bimetallic catalysts in the air purification.

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