scholarly journals Support Effect on the Performance of Ni2P Catalysts in the Hydrodeoxygenation of Methyl Palmitate

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 515 ◽  
Author(s):  
Irina Deliy ◽  
Ivan Shamanaev ◽  
Pavel Aleksandrov ◽  
Evgeny Gerasimov ◽  
Vera Pakharukova ◽  
...  
Keyword(s):  
Methyl Palmitate ◽  
Reduction Method ◽  
Catalytic Properties ◽  
Acid Sites ◽  
Nickel Phosphide ◽  
Nmr Techniques ◽  
31P Mas Nmr ◽  
Temperature Programmed ◽  
Effect Of Support ◽  
The Comparative Study

The effect of support nature, SiO2 and γ-Al2O3, on physicochemical and catalytic properties of nickel phosphide catalysts in methyl palmitate hydrodeoxygenation (HDO) has been considered. Firstly, alumina-supported nickel phosphide catalysts prepared by temperature-programmed reduction method starting from different precursors (phosphate–Ni(NO3)2 and (NH4)2HPO4 or phosphite–Ni(OH)2 and H3PO3) were compared using elemental analysis, N2 physisorption, H2-TPR, XRD, TEM, NH3-TPD, 27Al and 31P MAS NMR techniques and catalytic experiments. The mixture of nickel phosphide phases was produced from phosphate precursor on alumina while using of phosphite precursor provides Ni2P formation with the higher activity in methyl palmitate HDO. Besides, the comparative study of the performances of Ni2P/SiO2 and Ni2P/Al2O3 catalysts demonstrates the apparent superiority of alumina-supported Ni2P in the methyl palmitate hydrodeoxygenation. Considering the tentative scheme of methyl palmitate transformation, we proposed that cooperation of Ni2P and acid sites on the surface of alumina provides the enhanced activity of alumina-supported Ni2P through the acceleration of acid-catalysed hydrolysis.

Effect of precursor on the catalytic properties of Ni2P/SiO2 in methyl palmitate hydrodeoxygenation

RSC Advances ◽  
2016 ◽  
Vol 6 (36) ◽  
pp. 30372-30383 ◽  
Author(s):  
Ivan V. Shamanaev ◽  
Irina V. Deliy ◽  
Pavel V. Aleksandrov ◽  
Evgeny Yu. Gerasimov ◽  
Vera P. Pakharukova ◽  
...  
Keyword(s):  
Methyl Palmitate ◽  
Model Compound ◽  
Catalytic Properties ◽  
Nickel Phosphide ◽  
Phosphorus Precursor

The effect of phosphorus precursor on the physicochemical and catalytic properties of silica-supported nickel phosphide catalysts in the hydrodeoxygenation (HDO) of aliphatic model compound methyl palmitate (C15H31COOCH3) has been considered.

A Comparison Between the Structural and Catalytic Properties of Supported W2C, WC and WC1−x

1996 ◽  
Vol 454 ◽  
Author(s):  
Saemin Choi ◽  
Levi T. Thompson
Keyword(s):  
Catalytic Properties ◽  
Synthesis Temperature ◽  
Acid Sites ◽  
Tungsten Carbides ◽  
X Ray ◽  
Different Types ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Butane Conversion ◽  
Final Synthesis

ABSTRACTA series of γ-Al2O3 and SiO2 supported tungsten carbides was synthesized by the temperature programmed reaction of supported tungstates with CH4/H2 mixtures. The three known phases, W2C, WC and WC1−x, were evaluated as butane dehydrogenation catalysts. The microstructure and composition of the supported carbides depended on the loading and final synthesis temperature. The low and medium loaded materials were x-ray amorphous suggesting highly dispersed carbide domains on the support. The high loaded materials possessed small crystallites of W2C, WC or WC1-x. The supported carbides were as active as a commercial dehydrogenation catalyst with comparable selectivities in several cases. The butane conversion activity decreased in the following order: W2C > WC > WC1-x. The dehydrogenation selectivity decreased as the activity increased. The results suggest that there were two different types of sites, those catalyzing the selective dehydrogenation of butane and those capable of butane hydrogenolysis. The activity of these latter sites declined significantly with time on stream. We believe the hydrogenolysis activity was due to acid sites on the supported carbides.

Effects of SiO2/Al2O3 Ratio on Physicochemical Properties and Catalytic Performance of the Non-Templated ZSM-5 Zeolite

2011 ◽  
Vol 197-198 ◽  
pp. 992-995
Author(s):  
Wei Qiao Liu ◽  
Wei Ning Lei ◽  
Tong Ming Shang ◽  
Zhi Gang Mou ◽  
Heng Qiang Wang ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Acid Sites ◽  
X Ray Diffraction ◽  
Lewis Acid Sites ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

The ZSM-5 zeolites of various SiO2/Al2O3ratios were synthesized without using any template agent. X-ray diffraction (XRD), transmission electron microscope (TEM), temperature- programmed desorption of ammonia (NH3-TPD) and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to analyze the natures of the as-synthesized zeolite. The results show that the as-synthesized non-templated ZSM-5 zeolite is very pure. Meanwhile, Lewis acid sites and Bronsted acid sites are all presented in the as-synthesized non-templated HZSM-5 zeolite. The number of acid sites decreases almost linearly with the increasing of SiO2/Al2O3ratio of the zeolite. In addition, the reaction of propylene oligomerization was carried out over the as-synthesized non-templated HZSM-5 zeolite to evaluate the catalytic properties. The results show that the catalytic activity of propylene oligomerization decreases with the increasing of SiO2/Al2O3ratio.

scholarly journals Promotional Effects of Rare-Earth Praseodymium (Pr) Modification over MCM-41 for Methyl Mercaptan Catalytic Decomposition

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 400
Author(s):  
Xiaohua Cao ◽  
Jichang Lu ◽  
Yutong Zhao ◽  
Rui Tian ◽  
Wenjun Zhang ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Catalytic Decomposition ◽  
Product Distribution ◽  
Acid Sites ◽  
Methyl Mercaptan ◽  
Praseodymium Oxide ◽  
X Ray ◽  
Xps Characterization ◽  
Temperature Programmed ◽  
Mcm 41

Praseodymium (Pr)-promoted MCM-41 catalyst was investigated for the catalytic decomposition of methyl mercaptan (CH3SH). Various characterization techniques, such as X-ray diffraction (XRD), N2 adsorption–desorption, temperature-programmed desorption of ammonia (NH3-TPD) and carbon dioxide (CO2-TPD), hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectrometer (XPS), were carried out to analyze the physicochemical properties of material. XPS characterization results showed that praseodymium was presented on the modified catalyst in the form of praseodymium oxide species, which can react with coke deposit to prolong the catalytic stability until 120 h. Meanwhile, the strong acid sites were proved to be the main active center over the 10% Pr/MCM-41 catalyst by NH3-TPD results during the catalytic elimination of methyl mercaptan. The possible reaction mechanism was proposed by analyzing the product distribution results. The final products were mainly small-molecule products, such as methane (CH4) and hydrogen sulfide (H2S). Dimethyl sulfide (CH3SCH3) was a reaction intermediate during the reaction. Therefore, this work contributes to the understanding of the reaction process of catalytic decomposition methyl mercaptan and the design of anti-carbon deposition catalysts.

Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in α,β-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites

2021 ◽  
Author(s):  
Muhammad Zahid ◽  
Jiang Li ◽  
Ahmed Ismail ◽  
Francisco Zaera ◽  
Yujun Zhu
Keyword(s):  
Synergistic Effect ◽  
Reduction Method ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Unsaturated Aldehydes ◽  
Uniform Dispersion ◽  
Carbonyl Bond ◽  
Method Show ◽  
Intermetallic Nanoparticles

PtCo/MIL-101(Cr) with high uniform dispersion Pt–Co IMNs synthesized by a polyol reduction method show higher activity for selective catalytic hydrogenation of α,β-unsaturated aldehydes due to the synergistic effect of PtCo and MIL-101(Cr) support.

scholarly journals Tungsten Oxide-Modified SSZ-13 Zeolite as an Efficient Catalyst for Ethylene-To-Propylene Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 553
Author(s):  
Mansurbek Urol ugli Abdullaev ◽  
Sungjune Lee ◽  
Tae-Wan Kim ◽  
Chul-Ung Kim
Keyword(s):  
Tungsten Oxide ◽  
Fixed Bed ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
X Ray ◽  
Propylene Selectivity ◽  
Temperature Programmed

Among the zeolitic catalysts for the ethylene-to-propylene (ETP) reaction, the SSZ-13 zeolite shows the highest catalytic activity based on both its suitable pore architecture and tunable acidity. In this study, in order to improve the propylene selectivity further, the surface of the SSZ-13 zeolite was modified with various amounts of tungsten oxide ranging from 1 wt% to 15 wt% via a simple incipient wetness impregnation method. The prepared catalysts were characterized with several analysis techniques, specifically, powder X-ray diffraction (PXRD), Raman spectroscopy, temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of ammonia (NH3-TPD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and N2 sorption, and their catalytic activities were investigated in a fixed-bed reactor system. The tungsten oxide-modified SSZ-13 catalysts demonstrated significantly improved propylene selectivity and yield compared to the parent H-SSZ-13 catalyst. For the tungsten oxide loading, 10 wt% loading showed the highest propylene yield of 64.9 wt%, which was 6.5 wt% higher than the pristine H-SSZ-13 catalyst. This can be related to not only the milder and decreased strong acid sites but also the diffusion restriction of bulky byproducts, as supported by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) observation.

scholarly journals Influence of Sulfur-Containing Sodium Salt Poisoned V2O5–WO3/TiO2 Catalysts on SO2–SO3 Conversion and NO Removal

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 541 ◽  
Author(s):  
Haiping Xiao ◽  
Chaozong Dou ◽  
Hao Shi ◽  
Jinlin Ge ◽  
Li Cai
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Impregnation Method ◽  
So2 Oxidation ◽  
Sodium Salts ◽  
X Ray ◽  
Temperature Programmed ◽  
Physical Features

A series of poisoned catalysts with various forms and contents of sodium salts (Na2SO4 and Na2S2O7) were prepared using the wet impregnation method. The influence of sodium salts poisoned catalysts on SO2 oxidation and NO reduction was investigated. The chemical and physical features of the catalysts were characterized via NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that sodium salts poisoned catalysts led to a decrease in the denitration efficiency. The 3.6% Na2SO4 poisoned catalyst was the most severely deactivated with denitration efficiency of only 50.97% at 350 °C. The introduction of SO42− and S2O72− created new Brønsted acid sites, which facilitated the adsorption of NH3 and NO reduction. The sodium salts poisoned catalysts significantly increased the conversion of SO2–SO3. 3.6%Na2S2O7 poisoned catalyst had the strongest effect on SO2 oxidation and the catalyst achieved a maximum SO2–SO3-conversion of 1.44% at 410 °C. Characterization results showed sodium salts poisoned catalysts consumed the active ingredient and lowered the V4+/V5+ ratio, which suppressed catalytic performance. However, they increased the content of chemically adsorbed oxygen and the strength of V5+=O bonds, which promoted SO2 oxidation.

scholarly journals Liquid Phase Benzylation of Toluene over Modified Titania Catalysts

2012 ◽  
Vol 11 (2) ◽  
pp. 31-44
Author(s):  
Sunaja Devi K R ◽  
Sugunan S
Keyword(s):  
Liquid Phase ◽  
Lewis Acid ◽  
Benzyl Chloride ◽  
Sol Gel ◽  
Active Phase ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Sulfated Titania ◽  
Temperature Programmed

Titania, sulfated titania and a series of iron loaded sulfated titania catalyst with different iron loadings (39 %) are prepared by sol-gel method and calcined at 500°C. Anatase is found to be the active phase with crystallite size in the nano range. All the prepared catalysts are found to be stable up to 700°C. Acidity is measured using spectrophotometric monitoring of adsorption of perylene, thermogravimetric desorption of 2,6-dimethylpyridine and temperature programmed desorption of ammonia. The activities of the catalysts were tested for liquid phase Friedel-Crafts benzylation of toluene with benzyl chloride. It has been concluded that Lewis acid sites are responsible for the reaction.

In situ synthesis of Ni nanofibers via vacuum thermal reduction and their efficient catalytic properties for hydrogen generation

2018 ◽  
Vol 6 (24) ◽  
pp. 11370-11376 ◽  
Author(s):  
Qinglong Fu ◽  
Pan Yang ◽  
Jingchuan Wang ◽  
Hefang Wang ◽  
Lijun Yang ◽  
...  
Keyword(s):  
Reduction Method ◽  
Hydrogen Generation ◽  
Catalytic Properties ◽  
Decomposition Reaction ◽  
Thermal Reduction ◽  
In Situ Synthesis ◽  
Hydrazine Decomposition

Ni nanofibers have been prepared by a vacuum thermal reduction method, and further used as efficient catalysts for hydrogen generation from hydrous hydrazine decomposition reaction.

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