scholarly journals Spherical Silica Modified with Magnesium and Ruthenium—Synthesis, Characterization and Catalytic Properties

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7378
Author(s):  
Kalina Grzelak ◽  
Maciej Trejda
Keyword(s):  
Bimetallic Catalysts ◽  
Levulinic Acid ◽  
Catalytic Properties ◽  
Porous Silica ◽  
N2 Adsorption ◽  
Catalytic Activities ◽  
Spherical Silica ◽  
Cascade Processes ◽  
Adsorption Desorption ◽  
Positive Effect

The design of different bimetallic catalysts is an important area of catalytic research in the context of their possible applications in the cascade processes, meeting the requirements of the so-called green chemistry. In this study, such catalysts were obtained by the incorporation of magnesium species into spherical silica, which was in the next step covered with porous silica and modified with ruthenium species. The structure and chemical composition of the materials obtained were determined by XRD measurements, low temperature N2 adsorption/desorption, SEM, ICP-OES and XPS methods. The catalytic activities of materials obtained were tested in 2-propanol decomposition and hydrogenation of levulinic acid. The results obtained confirmed the successful coverage of nanospheres with porous silica. A much higher concentration of ruthenium species was found on the surface of the catalysts than in their bulk. The opposite relationship was observed for magnesium species. The modification of nanospheres with silica had a positive effect on the catalytic activity of the materials obtained. For the most active sample, i.e., Ru/NS/3Mg/NS, 49% of levulinic acid conversion in its hydrogenation process was reported with γ-valerolactone as the only product.

FEATURES AND CATALYTIC PROPERTIES OF RhCu: A REVIEW

2010 ◽  
Vol 24 (25n26) ◽  
pp. 5128-5138 ◽  
Author(s):  
SILVIA GONZALEZ ◽  
CARMEN SOUSA ◽  
FRANCESC ILLAS
Keyword(s):  
Catalytic Activity ◽  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Catalytic Activities ◽  
Cu Content ◽  
Bimetallic System

The study of bimetallic catalysts has scientific and technologic importance because of special catalytic activity towards several reactions. RhCu is an interesting bimetallic system due to combination of the very different catalytic activities of Rh and Cu. The catalytic activity of this bimetallic does not result from simple interpolation of the constituents. In fact, at low Cu content, the catalytic activity of RhCu is superior to that of Rh but when the Cu content is higher the activity decays. This is a curious trend which theoretical works had attempted to explain. This paper reports an overview of the most recent research works about this bimetallic system with emphasis in its especial characteristics.

Ammoxidation of 3-Picoline over V2O5/TiO2 Catalysts: Effects of TiO2 Supports on the Catalytic Performance

2011 ◽  
Vol 396-398 ◽  
pp. 791-797 ◽  
Author(s):  
Fu Min Zhang ◽  
Fei Chen ◽  
Qiang Xiao ◽  
Yi Jun Zhong ◽  
Wei Dong Zhu
Keyword(s):  
Catalytic Properties ◽  
External Surface ◽  
Weak Interactions ◽  
Catalytic Performance ◽  
Vanadium Oxides ◽  
Active Species ◽  
Direct Oxidation ◽  
N2 Adsorption ◽  
Wet Impregnation ◽  
Adsorption Desorption

A series of V2O5/TiO2catalysts were prepared by wet impregnation, and these prepared catalysts were characterized by XRD, N2 adsorption-desorption, H2-TPR, and TEM techniques and used in the selective ammoxidation of 3-picoline to 3-cyanopyridine. The effects of TiO2 supports on the catalytic properties of the resulting catalysts for the ammoxidation of 3-picoline to 3-cyanopyridine were investigated in detail. It is found that the V5+/V4+ transformation during ammoxidation is more favorable than the V5+/V3+ transformation for the selective ammoxidation of 3-picoline to 3-cyanopyridine. The V2O5/TiO2catalysts prepared from the nanosized TiO2particles as supports show a high activity for the direct oxidation of 3-picoline by air, resulting Subscript text Subscript textin a low selectivity for 3-cyanopyridine. This could be due to the fact that the active species vanadium oxides could be only supported on the external surface of the nano-sized TiO2particles with very minor contact area, leading to the weak interactions between active species and support.

scholarly journals Synthesis, characterization and catalytic properties of SAPO-11 molecular sieve synthesized in hydrothermal media using di-isopropylamine as template

2014 ◽  
Vol 62 (3) ◽  
pp. 481-488 ◽  
Author(s):  
T. Chellappa ◽  
M. Jose Fonseca Costa ◽  
W.A. Nascimento ◽  
L. Ferreira De Lima ◽  
I. Almeida Bassan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieve ◽  
Catalytic Properties ◽  
Single Agent ◽  
Catalytic Performance ◽  
Organic Template ◽  
N2 Adsorption ◽  
Bet Analysis ◽  
High Crystallization ◽  
Adsorption Desorption

Abstract A microporous SAPO-11 Molecular sieve was successfully synthesized by the hydrothermal method, using a single agent, as an organic template: di-isopropylamine (DIPA). The obtained solid was calcined at 550◦C for three hours, after which the flow of nitrogen was exchanged for that of synthetic air and submitted for another ten hours of calcination, so as to remove the single agent: di-isopropylamine, which after the removal of the template could be observed by the high crystallization of the sample. Furthermore, the molecular sieve was characterized by XRD, SEM, TG-DTG and N2 adsorption desorption (BET analysis). The obtained catalyst proved to have a high potential catalytic activity and selectivity, through the obtained characterization results, exhibiting good hydrothermal stability. The catalytic performance of SAPO-11 was tested by the deactivation/regenerability of the coked sample, furthered by cracking of n-hexane reaction and high olefins selectivity was obtained.

scholarly journals Synergy between Ni and Co Nanoparticles Supported on Carbon in Guaiacol Conversion

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2199
Author(s):  
Elodie Blanco ◽  
Ana Belen Dongil ◽  
Néstor Escalona
Keyword(s):  
Liquid Phase ◽  
Bimetallic Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
N2 Adsorption ◽  
Nickel Cobalt ◽  
Co Nanoparticles ◽  
Adsorption Desorption

Nickel-cobalt bimetallic catalysts supported on high surface area graphite with different Ni:Co ratios (3:1, 2:1 and 1:1) and the monometallic Ni and Co were prepared by wetness impregnation method. The catalysts were tested in hydrodeoxygenation (HDO) of guaiacol in the liquid phase at 50 bar of H2 and 300 °C. The materials were characterized by N2 adsorption–desorption, XRD, TEM/STEM, H2-TPR, and CO-chemisorption to assess their properties and correlate them with the catalytic results. The activity was higher on the bimetallic catalysts and followed the trend NiCo2:1/G ∼ NiCo3:1/G > NiCo1:1/G > Co/G > Ni/G. Also, selectivity results showed that Ni was more active in the hydrogenation favoring cyclohexanol production from phenol, while this was inhibited on the Co-containing catalysts. Hence, the results showed that synergy was created between Ni and Co and that their interaction, properties, and catalytic performance depend on the metals’ ratio.

scholarly journals Recent Development of Renewable Diesel Production Using Bimetallic Catalysts

2021 ◽  
Vol 9 ◽  
Author(s):  
Shir Reen Chia ◽  
Saifuddin Nomanbhay ◽  
Mei Yin Ong ◽  
Kit Wayne Chew ◽  
Kuan Shiong Khoo ◽  
...  
Keyword(s):  
Energy Source ◽  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Renewable Diesel ◽  
Practical Solution ◽  
Catalytic Activities ◽  
Monometallic Catalysts ◽  
Synergistic Interactions ◽  
End Products ◽  
Diesel Production

Renewable diesel as a potential sustainable energy source in future requires catalysts to convert the feedstocks into end products. Among various type of catalysts, bimetallic catalysts are widely applied in the renewable diesel production due to their unique catalytic properties and enhanced catalytic activities, which differ from their parent monometallic catalysts. This mini review comprised of the brief introduction on technologies in producing renewable diesel and aims to discuss the underneath knowledge of synergistic interactions in bimetallic catalysts that synthesized through various techniques. The novelty of this review reveals the recent development of renewable diesel production, highlighting the mechanisms of bimetallic catalysts in the enhancement of the catalytic activity, and exploring their possibilities as practical solution in industrial production.

Preparation of SBA-15 supported Pt/Pd bimetallic catalysts using supercritical fluid reactive deposition: how do solvent effects during material synthesis affect catalytic properties?

2017 ◽  
Vol 19 (4) ◽  
pp. 977-986 ◽  
Author(s):  
Y. Qiao ◽  
N. Said ◽  
M. Rauser ◽  
K. Yan ◽  
F. Qin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Fluid ◽  
Solvent Effects ◽  
Bimetallic Catalysts ◽  
Levulinic Acid ◽  
Catalytic Properties ◽  
Reaction Medium ◽  
Material Synthesis ◽  
Catalyst Synthesis ◽  
Reactive Deposition

Supercritical carbon dioxide is the preferred reaction medium for catalyst synthesis as exemplified for the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL).

scholarly journals Catalytic Diversity of GH30 Xylanases

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4528
Author(s):  
Katarína Šuchová ◽  
Vladimír Puchart ◽  
Nikolaj Spodsberg ◽  
Kristian B. R. Mørkeberg Krogh ◽  
Peter Biely
Keyword(s):  
Methyl Ester ◽  
Catalytic Properties ◽  
Specific Activity ◽  
Current Knowledge ◽  
Carboxyl Group ◽  
Weak Effect ◽  
Bacterial Enzymes ◽  
Catalytic Activities ◽  
Almost All ◽  
Free Carboxyl

Catalytic properties of GH30 xylanases belonging to subfamilies 7 and 8 were compared on glucuronoxylan, modified glucuronoxylans, arabinoxylan, rhodymenan, and xylotetraose. Most of the tested bacterial GH30-8 enzymes are specific glucuronoxylanases (EC 3.2.1.136) requiring for action the presence of free carboxyl group of MeGlcA side residues. These enzymes were not active on arabinoxylan, rhodymenan and xylotetraose, and conversion of MeGlcA to its methyl ester or its reduction to MeGlc led to a remarkable drop in their specific activity. However, some GH30-8 members are nonspecific xylanases effectively hydrolyzing all tested substrates. In terms of catalytic activities, the GH30-7 subfamily is much more diverse. In addition to specific glucuronoxylanases, the GH30-7 subfamily contains nonspecific endoxylanases and predominantly exo-acting enzymes. The activity of GH30-7 specific glucuronoxylanases also depend on the presence of the MeGlcA carboxyl, but not so strictly as in bacterial enzymes. The modification of the carboxyl group of glucuronoxylan had only weak effect on the action of predominantly exo-acting enzymes, as well as nonspecific xylanases. Rhodymenan and xylotetraose were the best substrates for exo-acting enzymes, while arabinoxylan represented hardly degradable substrate for almost all tested GH30-7 enzymes. The results expand current knowledge on the catalytic properties of this relatively novel group of xylanases.

Facile Preparation of Nanoporous SnO2 for Application in Photodegradation of Methylene Blue

2011 ◽  
Vol 194-196 ◽  
pp. 385-388
Author(s):  
Hong Juan Wang ◽  
Feng Qiang Sun ◽  
Ming Zhong Ren ◽  
Qing Wei Guo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
High Photocatalytic Activity ◽  
N2 Adsorption ◽  
Photochemical Method ◽  
Degussa P25 ◽  
Adsorption Desorption

Nanoporous SnO2with high photocatalytic activity has been successfully prepared by a photochemical method, using SnCl2aqueous solution as a precursor. The as-synthesized sample was characterized by XRD, N2 adsorption-desorption and UV-vis. The photocatalytic activity of the sample was evaluated by degrading methylene blue (MB) aqueous solution under the UV light source and was compared with that of the commercial titania (Degussa P25). The results showed that the produced SnO2can degrade MB solution quickly and has comparative photocatalytic performance with P25 for degrading MB. This facile method supplies an effective way to prepare SnO2photocatalyst.

Influence of the thermal treatment conditions and composition of bimetallic catalysts Fe—Pd/SiO2 on the catalytic properties in phenylacetylene hydrogenation

2016 ◽  
Vol 65 (2) ◽  
pp. 432-439 ◽  
Author(s):  
A. A. Shesterkina ◽  
L. M. Kozlova ◽  
O. A. Kirichenko ◽  
G. I. Kapustin ◽  
I. V. Mishin ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Treatment Conditions

Effect of L-Arginine on the Carbon Microsphere Forming under Hydrothermal Carbonization

2019 ◽  
Vol 41 (1) ◽  
pp. 72-72
Author(s):  
Jilei Liang Jilei Liang ◽  
Mengmeng Wu Mengmeng Wu ◽  
Hongmei Cai Hongmei Cai ◽  
Hao Wang Hao Wang ◽  
Hua Huang Hua Huang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Adsorption Capacity ◽  
Surface Property ◽  
Condensation Reaction ◽  
Hydrothermal Carbonization ◽  
Carbon Microspheres ◽  
N2 Adsorption ◽  
Sem Images ◽  
Ft Ir ◽  
Adsorption Desorption

Carbon microspheres (CMs) with a diameter of 5-10 μm have been synthesized by hydrothermal carbonization of starch and L-arginine. The surface property and structure of CMs were examined by FT-IR spectra, N2 adsorption-desorption isotherms and SEM images. These characterizations indicated that the L-arginine does not connect into the CMs but it promotes the starch hydrolysis and polymerization-condensation reaction of intermediate, which accelerates the formation of CMs and improves the yield in shorter time. The surface property of CMs determines adsorption capacity for acetic acid. By contrast, the porosity resulted from the carbonization at 500 and#176;C dominates the adsorption capacity for acetic acid.

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