Rhenium and manganese modified activated carbon as catalyst for methanol decomposition

2007 ◽  
Vol 85 (2) ◽  
pp. 118-123 ◽  
Author(s):  
T Tsoncheva ◽  
S Vankova ◽  
O Bozhkov ◽  
D Mehandjiev
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Carbon Materials ◽  
Catalytic Properties ◽  
Methanol Decomposition ◽  
Complex Character ◽  
Active Centre ◽  
Modified Activated Carbon

Bicomponent manganese and rhenium modified activated carbon materials, prepared by different methods, are studied and compared with the corresponding monocomponent materials as catalysts in methanol decomposition to CO and hydrogen. The best catalytic activity and stability is observed for the sample obtained by simultaneous deposition of Mn and Re precursors. The complex character of the catalytic active centre, including manganese and rhenium irons in various oxidative states, is discussed. The determining role of the Mn(II) ions in the improvement of the catalytic properties is assumed.Key words: rhenium, manganese, activated carbon, methanol decomposition.

scholarly journals Role of CO2 During Oxidative Dehydrogenation of Propane Over Bulk and Activated-Carbon Supported Cerium and Vanadium Based Catalysts

2021 ◽  
Author(s):  
Petar Djinović ◽  
Janez Zavašnik ◽  
Janvit Teržan ◽  
Ivan Jerman
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Oxidative Dehydrogenation ◽  
Active Phase ◽  
Lattice Oxygen ◽  
Chemisorbed Oxygen ◽  
Catalytically Active ◽  
Temperature Programmed ◽  
Propane Cracking

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract

An effective approach for modifying carbonaceous materials with niobium single sites to improve their catalytic properties

2015 ◽  
Vol 44 (46) ◽  
pp. 19956-19965 ◽  
Author(s):  
A. S. Bozzi ◽  
R. L. Lavall ◽  
T. E. Souza ◽  
M. C. Pereira ◽  
P. P. de Souza ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Activated Carbon ◽  
Carbon Materials ◽  
Catalytic Properties ◽  
Carbonaceous Materials ◽  
Simple Route ◽  
Catalytically Active

In this paper we show a very simple route for the incorporation of catalytically active niobium species on the surface of carbon materials, such as graphene oxide, carbon nanotubes and activated carbon.

How does the Support Influence the Catalytic Activity of the Keggin Ion?

1996 ◽  
Vol 454 ◽  
Author(s):  
Zakiyyah Smith ◽  
Michael Palmieri ◽  
Nancy Buecheler ◽  
Susan A. Jansen
Keyword(s):  
Catalytic Activity ◽  
Carbon Materials ◽  
Solid Acid ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Heteropoly Acids ◽  
Keggin Ion ◽  
Oxide Substrates ◽  
Silica Matrices

AbstractHeteropoly acids, HPA are well known solid acid and oxidation catalysts that find application in hetergeneous and homogeneous reactions. In the former, surface area and stability problems are diminshed by supporting the HPA. Typical supports include oxide substrates and porous carbon materials. The HPA's show some instability on these supports however. In this work, we demonstrate that HPA encapsulated in sol-gel silica matrices show enhanced catalytic performance without compromising the catalytic activity of the HPA. In addition, the specific role of the support in the catalytic process is described as well.

Catalytic Properties of Ni3Fe Foil for Hydrogen Production from Methanol

2012 ◽  
Vol 706-709 ◽  
pp. 1052-1057 ◽  
Author(s):  
Ya Xu ◽  
Masahiko Demura ◽  
Toshiyuki Hirano ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi
Keyword(s):  
Catalytic Activity ◽  
Fine Structure ◽  
Hydrogen Production ◽  
Surface Structure ◽  
Carbon Nanofibers ◽  
Surface Analysis ◽  
Catalytic Properties ◽  
Methanol Decomposition ◽  
Metallurgical Process ◽  
Temperature Surface

The objective of this study is to investigate the catalytic properties of intermetallic Ni3Fe foil. We fabricated Ni3Fe foil of 30 µm in thickness by a metallurgical process, and examined the catalytic activity of the Ni3Fe foil for methanol decomposition from 513 to 973 K. The Ni3Fe foil showed activity for methanol decomposition above 623 K. The activity increased with the increase of reaction temperature. Surface analysis revealed that a surface structure of fine Ni-Fe particles dispersed on carbon nanofibers was formed on the foil during the reaction. The activity is attributed to the formation of this fine structure.

scholarly journals The Enhanced Performance of N-Modified Activated Carbon Promoted with Ce in Selective Catalytic Reduction of NOx with NH3

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1423
Author(s):  
Marwa Saad ◽  
Agnieszka Szymaszek ◽  
Anna Białas ◽  
Bogdan Samojeden ◽  
Monika Motak
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Reduction Mechanism ◽  
Modified Activated Carbon ◽  
Oxidation Reduction ◽  
Reduction Of Nox

The goal of the study was to modify activated carbon (AC) with nitrogen groups and ceria and to test the obtained materials in low temperature selective catalytic reduction of nitrogen oxides. For that purpose, the starting AC was oxidized with HNO3 of various concentrations, modified with urea and doped with 0.5 wt.% of Ce. It was observed that the increased concentration of acid influenced the catalytic activity, since textural and surface chemistry of activated carbon was changed. The most active sample was that modified with 14 M HNO3 and it reached 96% of NO conversion at 300 °C. Additionally, the addition of Ce improved the catalytic performance of modified AC, and NO was reduced according to oxidation–reduction mechanism, characteristic for supported metal oxides. Nevertheless, the samples promoted with Ce emitted significantly higher amount of CO2 comparing to the non-promoted ones.

scholarly journals Synthesis of Novel Heteroleptic Oxothiolate Ni(II) Complexes and Evaluation of Their Catalytic Activity for Hydrogen Evolution

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 401
Author(s):  
Fotios Kamatsos ◽  
Kostas Bethanis ◽  
Christiana A. Mitsopoulou
Keyword(s):  
Catalytic Activity ◽  
Catalytic Properties ◽  
Spectroscopic Methods ◽  
Electrochemical Studies ◽  
X Ray Diffraction ◽  
Neutral Form ◽  
Proton Reduction ◽  
X Ray ◽  
Better Than

Two heteroleptic nickel oxothiolate complexes, namely [Ni(bpy)(mp)] (1) and [Ni(dmbpy)(mp)] (2), where mp = 2-hydroxythiophenol, bpy = 2,2′-bipyridine and dmbpy = 4,4′-dimethyl-2,2′-bipyridine were synthesized and characterized with various physical and spectroscopic methods. Complex 2 was further characterized by single crystal X-ray diffraction data. The complex crystallizes in the monoclinic P 21/c system and in its neutral form. The catalytic properties of both complexes for proton reduction were evaluated with photochemical and electrochemical studies. Two different in their nature photosensitizers, namely fluorescein and CdTe-TGA-coated quantum dots, were tested under various conditions. The role of the electron donating character of the methyl substituents was revealed in the light of the studies. Thus, catalyst 2 performs better than 1, reaching 39.1 TONs vs. 4.63 TONs in 3 h, respectively, in electrochemical experiments. In contrast, complex 1 is more photocatalytically active than 2, achieving a TON of over 6700 in 120 h of irradiation. This observed reverse catalytic activity suggests that HER mechanism follows different pathways in electrocatalysis and photocatalysis.

scholarly journals Dehydration of isopropyl alcohol with activated carbon functionalized with Br- and S-containing reagents

2021 ◽  
pp. 90-99
Author(s):  
L.M. Grishchenko ◽  
◽  
A.N. Zaderko ◽  
G.G. Tsapyuk ◽  
I.P. IMatushko ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Isopropyl Alcohol ◽  
Surface Concentration ◽  
Complete Conversion ◽  
Modified Activated Carbon ◽  
Liquid Bromine ◽  
Catalytically Active ◽  
Hydrolysis Conditions ◽  
Sulfur Containing

Bromination of activated carbon GSGD was performed and active bromine-containing precursors were obtained, in which bromine is capable of being replaced by sulfur-containing functional groups. Bromination with liquid bromine and a solution of bromine in potassium bromide at room temperature leads to the introduction of 0.44–0.45 mmol g–1 of bromine into the surface layer of activated carbon. The treatment of brominated samples with sulfur-containing reagents with subsequent oxidation allows obtaining carbon samples that are catalytically active in the dehydration reaction of isopropyl alcohol in a gas phase. The temperature of complete conversion of isopropyl alcohol to propylene is a measure of catalytic activity. The concentration of sulfogroups in the prepared samples is up to 0.3 mol g–1. Thermogravimetry and thermoprogrammed desorption with mass spectrometric registration of products were used to study the thermal stability of modified activated carbon samples. The influence of the nature of brominating reagents, hydrolysis conditions and oxidation conditions on the structure, surface concentration of grafted S-containing groups and catalytic properties of the obtained materials was studied. Pre-bromination leads to an increase in the catalytic activity of activated carbon modified with sulfur-containing groups and the temperature of complete conversion of isopropyl alcohol to propylene decreases up to 400C depending on the concentration of sulfogroups.

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