scholarly journals Linear Hexane Isomerization Over Bimetallic Zeolite Catalysts

2021 ◽  
Vol 15 (3) ◽  
pp. 330-335
Author(s):  
Lyubov Patrylak ◽  
◽  
Oleksandra Pertko ◽  
Yuliya Voloshyna ◽  
Angela Yakovenko ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Maximum Yield ◽  
Nitrogen Adsorption ◽  
Zeolite Catalysts ◽  
Optimum Process ◽  
Mfi Zeolite ◽  
Hydrogen Form ◽  
Alkane Isomerization ◽  
Adsorption Desorption ◽  
Palladium Content

The aim of this study was to evaluate the activity and selectivity in isomerization of n-hexane of bimetallic zeolite catalysts containing a nickel transition metal in addition to palladium. Bimetallic bifunctional linear alkane isomerization catalysts based on the hydrogen form of MFI zeolite have been synthesized. The porous properties of the samples were investigated by means of low-temperature nitrogen adsorption/desorption, the size of the metal component – by TEM, and the catalytic properties – in the micro-pulse isomerization of n-hexane. Antisymbatic correlation between the temperature of the maximum yield of hexane isomers and the amount of nickel in the sample was found for a stable palladium content. The introduction of nickel allows to reduce the optimum process temperature from 598 to 523 K.

scholarly journals Effect of the Metal Deposition Order on Structural, Electronic and Catalytic Properties of TiO2-Supported Bimetallic Au-Ag Catalysts in 1-Octanol Selective Oxidation

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yulia Kotolevich ◽  
Ekaterina Pakrieva ◽  
Ekaterina Kolobova ◽  
Mario H. Farías ◽  
Nina Bogdanchikova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Catalytic Properties ◽  
Diffuse Reflectance Spectroscopy ◽  
Density Functional Theory Method ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
A Charge ◽  
Adsorption Desorption ◽  
Ag Catalysts

Au and Ag were deposited on TiO2 modified with Ce, La, Fe or Mg in order to obtain bimetallic catalysts to be used for liquid-phase oxidation of 1-octanol. The effects of the deposition order of gold and silver, and the nature of the support modifying additives and redox pretreatments on the catalytic properties of the bimetallic Au-Ag catalysts were studied. Catalysts were characterized by low-temperature nitrogen adsorption–desorption, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. It was found that pretreatments with hydrogen and oxygen at 300 °C significantly decreased the activity of AuAg catalysts (silver was deposited first) and had little effect on the catalytic properties of AgAu samples (gold was deposited first). The density functional theory method demonstrated that the adsorption energy of 1-octanol increased for all positively charged AuxAgyq (x + y = 10, with a charge of q = 0 or +1) clusters compared with the neutral counterparts. Lanthanum oxide was a very effective promoter for both monometallic and bimetallic gold and silver catalysts in the studied process.

scholarly journals Acidic and Catalytic Properties of Zeolites Modified by Zinc in the Conversion Process of Lower C3–C4 Alkanes

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 421
Author(s):  
Vladimir Erofeev ◽  
Vyacheslav Khasanov ◽  
Sofia Dzhalilova ◽  
Wladimir Reschetilowski ◽  
Anna Syskina ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Catalytic Properties ◽  
Zeolite Catalysts ◽  
Conversion Process ◽  
Additive Concentration ◽  
Liquid Hydrocarbons ◽  
Mfi Zeolite ◽  
Acid Properties ◽  
Alcohol Fraction ◽  
High Silica

The acid and catalytic properties of the modified MFI zeolite catalysts during the conversion of the propane–butane fraction of the associated petroleum gases into the aromatic hydrocarbons were studied. It was established that the high-silica zeolites synthesized with the new structure-forming additive of the alcohol fraction (ZKE-AF) belong to the high-silica MFI zeolites. The resulting zeolites were modified by 1–5 wt. % additives consisting of zinc oxide and sulfide. The influence of the modifying additive concentration containing zinc oxides and sulfides in an amount of 1–5% on the acid and catalytic properties of the catalysts in the conversion process of lower C3–C4 alkanes into liquid hydrocarbons was studied. The research of the acid properties of the modified zeolite catalysts by thermal desorption of ammonia showed that the total concentrations of the acidic centers of H-ZKE-AF modified by 3% and 5% ZnO increased. It was found that the highest yield of liquid hydrocarbons was on the zeolite catalysts modified by 3% and 5% ZnS, and is 60.6% and 60.5%, respectively, which is 9% more than in the initial H-ZKE-AF. The activity of the zeolite catalysts modified by zinc oxide and zinc sulfide was in correlation with their acid properties.

scholarly journals Processing of propane-butane fraction on zeolite-containing catalysts

2021 ◽  
Vol 340 ◽  
pp. 01016
Author(s):  
B.T. Tuktin ◽  
A.M. Temirova ◽  
A.A. Omarova
Keyword(s):  
Catalytic Properties ◽  
Raw Materials ◽  
Maximum Yield ◽  
Physicochemical Characteristics ◽  
Zeolite Catalysts ◽  
Light Hydrocarbons ◽  
Active Centers ◽  
Variable Valence ◽  
New Generation ◽  
Propane Butane

Abstarct. Processing of propane-butane and propane-propylene fractions in light hydrocarbons on the zeolite catalysts modified by zinc, manganese, cobalt, lanthanum was studied. It was shown that the degree of conversion on the Zn-La-Co-ZSM-AI2O3 catalyst increases from 40.2 to 99.0% as the temperature increasesfrom450to600 °C. The maximum yield of aromatic hydrocarbons was 31.4%. As the temperature increases from 450 to 600С, the cracking of hydrocarbons intensifies resulting in the formation of methane and ethane. New generation catalysts based on zeolites have the prospect of being used in technologies for processing various types of hydrocarbon raw materials. The activity of catalysts in the processing of light hydrocarbons depends on the structure and state of the active centers. The physicochemical characteristics of the developed catalysts have been studied. One of the possible ways to control the catalytic properties is to introduce a variable valence catalyst as modifiers into the composition.

scholarly journals Improvement of the Catalytic Efficiency of Butene Oligomerization Using Alkali Metal Hydroxide-Modified Hierarchical ZSM-5 Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 298 ◽  
Author(s):  
Lei Zhang ◽  
Ming Ke ◽  
Zhaozheng Song ◽  
Yang Liu ◽  
Wenbo Shan ◽  
...  
Keyword(s):  
Alkali Treatment ◽  
Catalytic Efficiency ◽  
Nitrogen Adsorption ◽  
Alkali Metal Hydroxide ◽  
Zeolite Catalysts ◽  
Liquid Fuels ◽  
Light Olefin ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

Oligomerization of light olefin is an effective method to produce plentiful liquid fuels. However, oligomerization processes using microporous zeolites have severe problems due to steric hindrance. In this paper, oligomerization of butene using a series of new types of hierarchical HZSM-5 zeolite catalysts is studied. To obtain the modified HZSM-5 catalysts, HZSM-5 is treated with the same concentration of LiOH, NaOH, KOH, and CsOH aqueous solutions, respectively. It is demonstrated that the alkali treatment can effectively modify the acidity properties and hierarchical structure of the HZSM-5 catalyst, which is confirmed by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Nitrogen Adsorption-desorption Measurements, Transmission Electron Microscopy Investigations (TEM), Ammonia Temperature-programmed Desorption Method (NH3-TPD), Pyridine FT-IR, and Thermogravimetric Analysis (TGA). The results show that hierarchical catalysts with interconnected open-mesopores, smaller crystal size, and suitable acidity can better prolong the catalyst lifetime during butene oligomerization. Particularly, the HZSM-5 catalysts treated with CsOH aqueous solution (ATHZ5-Cs) proved to be the most effective catalyst, resulting in approximately 99% conversion of butene and exhibiting C8+ selectivity of 85% within 12 h. Thus, an appropriate hierarchical catalyst can satisfy the oligomerization process and has the potential to be used as a substitute for the commercial ZSM-5 catalyst.

scholarly journals Conversion of the Propane–Butane Fraction into Arenes on MFI Zeolites Modified by Zinc Oxide and Activated by Low-Temperature Plasma

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2704
Author(s):  
Vladimir I. Erofeev ◽  
Sofiya N. Dzhalilova ◽  
Mikhail V. Erofeev ◽  
Vasilii S. Ripenko ◽  
Vladimir P. Reschetilowski
Keyword(s):  
Aromatic Hydrocarbons ◽  
Maximum Yield ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Silica Gels ◽  
Mfi Zeolite ◽  
Temperature Plasma ◽  
High Silica ◽  
Mfi Zeolites ◽  
Propane Butane

The effect of modification of MFI zeolite 1–5 wt.% ZnO activated by plasma on acid and catalytic properties in the conversion of the propane–butane fraction into arenes was investigated. The high-silica zeolites with silicate module 45 were synthesized from alkaline alumina–silica gels in the presence of an ‘X-oil’ organic structure-forming additive. The modification of the zeolite with zinc was carried out by impregnating the zeolite granules in the H-form with an aqueous solution of Zn(NO3)2. The obtained zeolites were characterized by X-ray phase analysis and IR spectroscopy. It is shown that the synthesized zeolites belong to the high-silica MFI zeolites. The study of microporous zeolite-containing catalysts during the conversion of C3-C4 alkanes to aromatic hydrocarbons made it possible to establish that the highest yield of aromatic hydrocarbons is observed on zeolite catalysts modified with 1 and 3% ZnO and amount to 63.7 and 64.4% at 600 °C, respectively, which is 7.7–8.4% more than on the original zeolite. The preliminary activation of microporous zeolites modified with 1–5% ZnO and plasma leads to an increase in the yield of aromatic hydrocarbons from the propane–butane fraction; the maximum yield of arenes is observed in zeolite catalysts modified with 1 and 3% ZnO and activated by plasma, amounting to 64.9 and 65.5% at 600 °C, respectively, which is 8.9–9.5% more than on the initial zeolite. The activity of the zeolite catalysts modified by ZnO and activated by plasma show good agreement with their acid properties. Activation of the zeolites modified by 1 and 3% ZnO and plasma leads to an increase in the concentration of the weak acid sites of the catalyst to 707 and 764 mmol/g in comparison with plasma-inactivated 1 and 3% ZnO/ZKE-XM catalysts at 626 and 572 mmol/g, respectively.

scholarly journals Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

Catalysts ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 2122-2133 ◽  
Author(s):  
Masakazu Iwamoto ◽  
Ryota Takezawa ◽  
Masao Morimoto
Keyword(s):  
Zinc Ion ◽  
Zeolite Catalysts ◽  
Mfi Zeolite

scholarly journals Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1519
Author(s):  
Jong Gyeong Kim ◽  
Sunghoon Han ◽  
Chanho Pak
Keyword(s):  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Electronic States ◽  
Nitrogen Adsorption ◽  
Reduction Reaction ◽  
Phosphorus Doping ◽  
X Ray ◽  
Precious Metal Catalysts ◽  
Adsorption Desorption

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

Effect of Carbon Pre-Treatment on Pd Dispersion in Synthesis of Pd/C Catalyst

2014 ◽  
Vol 804 ◽  
pp. 149-152 ◽  
Author(s):  
Ji Sun Kim ◽  
Jae Ho Baek ◽  
Myung Hwan Kim ◽  
Seong Soo Hong ◽  
Man Sig Lee
Keyword(s):  
Surface Area ◽  
Nitrogen Adsorption ◽  
Area Ratio ◽  
High Dispersion ◽  
Co Chemisorption ◽  
Pd Dispersion ◽  
Before And After ◽  
Pre Treatment ◽  
Treated Carbon ◽  
Adsorption Desorption

In this study, we confirmed effect of carbon pre-treatment on Pd dispersion in synthesis of Pd/C catalyst. Physical characteristics on the surface of before and after pre-treated carbon were analyzed by nitrogen adsorption-desorption analysis. The dispersion and size of Pd particles were analyzed by XRD, FE-TEM and CO-chemisorption. After pre-treatment, surface area of carbon were decreased. And mesopore area ratio were increased with decreasing micropore area ratio. In the case of pre-treated carbon, we confirmed high dispersion of Pd particles.

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