Some Research on the Magnetic X Zeolite Composites

X zeolite behaves excellent properties of shape selective catalysis, molecular sieves and iron-exchange for its unique tunnel structure and large specific surface area. In this paper magnetic core has been introduced into the zeolite structure and magnetic zeolite with high stability and adsorption properties have been prepared. Synthesis conditions and adsorption of Pb2+ also have been studied. Magnetic zeolite composite was hydrothermally synthesized with a traditional hydrothermal method by adding magnetic Fe3O4 suspension in the zeolite synthesis system. Synthesis conditions and adsorption of Pb2+ also have been studied. The products were characterized with X Ray diffraction (XRD), IR spectrometer (IR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Thermogravimetric (TGA) and differential scanning calorimetry (DSC) instruments. The results show that the products have an X zeolite crystal structure and present super paramagnetic properties. The saturation magnetization value of the product is about 3.7 emu•g-1. The weight ratio of magnetic Fe3O4 in the magnetic zeolite composite is calculated to be about 5%. The magnetic zeolite composites have high surface area and the absorption capability of the products is 196.8mg/g.

Download Full-text

Catalytic Activity of High-Surface-Area Amorphous MgO Obtained from Upsalite

Catalysts ◽

10.3390/catal11111338 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1338

Author(s):

Marek Gliński ◽

Ewa M. Iwanek (nee Wilczkowska) ◽

Urszula Ulkowska ◽

Agnieszka Czajka ◽

Zbigniew Kaszkur

Keyword(s):

Surface Area ◽

Carbonyl Compounds ◽

Main Product ◽

High Surface ◽

High Surface Area ◽

Hydrogenation Reaction ◽

Transfer Hydrogenation ◽

Reaction Conditions ◽

Synthesis Conditions ◽

Transfer Hydrogenation Reaction

The first aim of the research was to synthesize a pure Upsalite, which is an amorphous form of MgCO3, by modifying a procedure described in the literature, so that it would be the precursor of a high-surface, amorphous magnesium oxide. The results indicate that within the studied reaction conditions, the type of alcohol used as the reactant has the most pronounced effect on the yield of reaction. From the two alcohols that led to the highest yield of Upsalite, methanol gave a substantially larger surface area (794 vs. 191 m2 g−1). The optimized synthesis conditions of Upsalite were used to obtain MgO via thermolysis, whose activity in the transfer hydrogenation reaction (THR) from ethanol, 2-propanol and 2-pentanol to various carbonyl compounds was determined. The optimal conditions for the thermolysis were as follows: vacuum, T = 673 K as the final temperature, and a heating rate of 2 deg min−1. The high-surface, amorphous magnesia (SBET = 488 m2 g−1) was found to be a very selective catalyst to 4-t-butylcyclohexanone in THR, which led to a diastereoselectivity of over 94% to the E-isomer of 4-t-butylcyclohexanol for more than 3 h, with conversions of up to 97% with either 2-propanol or 2-pentanol as the hydrogen donor. In the case of acrolein and 2-n-propylacrolein being used as the hydrogen acceptors, the unsaturated alcohol (UOL) was the main product of the reaction, with higher UOL yields noted for ethanol than 2-propanol.

Download Full-text

An openwork like structures of polylactide – manufacturing and properties

E3S Web of Conferences ◽

10.1051/e3sconf/20184400165 ◽

2018 ◽

Vol 44 ◽

pp. 00165 ◽

Cited By ~ 1

Author(s):

Karolina Sobczyk ◽

Karol Leluk

Keyword(s):

Lactic Acid ◽

Surface Area ◽

High Surface ◽

High Surface Area ◽

Weight Ratio ◽

Electrospinning Process ◽

Poly Lactic Acid ◽

Process Conditions ◽

Fiber Morphology

Poly(lactic acid) electrospinning tests were carried out under various process conditions. Openwork structures with a high surface area to weight ratio have been obtained. Changing the parameters of the PLA electrospinning process resulted in products with different fiber morphology.

Download Full-text

High-Surface-Area Carbon Molecular Sieves for Selective CO2 Adsorption

ChemSusChem ◽

10.1002/cssc.201000083 ◽

2010 ◽

Vol 3 (8) ◽

pp. 974-981 ◽

Cited By ~ 253

Author(s):

Anass Wahby ◽

José M. Ramos-Fernández ◽

Manuel Martínez-Escandell ◽

Antonio Sepúlveda-Escribano ◽

Joaquín Silvestre-Albero ◽

...

Keyword(s):

Surface Area ◽

Molecular Sieves ◽

Co2 Adsorption ◽

High Surface ◽

High Surface Area ◽

Carbon Molecular Sieves

Download Full-text

Sol-Gel Synthesis of N-Doped Mesoporous TiO2 with High Crystallinity and High Visible Light Photocatalytic Activity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.857 ◽

2012 ◽

Vol 217-219 ◽

pp. 857-861 ◽

Cited By ~ 1

Author(s):

Xiao Ling Guo ◽

Xiang Dong Wang ◽

Feng He

Keyword(s):

Photocatalytic Activity ◽

Visible Light ◽

Surface Area ◽

Anatase Phase ◽

High Surface ◽

Sol Gel ◽

High Surface Area ◽

Weight Ratio ◽

Mesoporous Tio2 ◽

Vis Spectroscopy

N-doped mesoporous TiO2 with high surface area and crystallinity were synthesized by sol-gel method using polyacrylamide (PAM) and polyethylene glycol (PEG) as the complex templates. The resulting materials were characterized by XRD, TEM, N2 adsorption-desorption, and UV-Vis spectroscopy. It is found that when the weight ratio of PAM and PEG is 1:4, the sample, prepared at 600 °C in nitrogen and at 500 °C in air, is anatase phase and has high surface area and crystallinity. The particle size and pore size of the sample are about 10 nm and 17 nm respectively. Compared with that of the undoped mesoporous TiO2, the absorption band edges of N-doped samples exhibit an evident red-shift. The results of the photocatalytic degradation of methyl orange (MO) show that N-doped sample appears to have higher photocatalytic activity under visible light than undoped sample.

Download Full-text

Synthesis, characterization, and reactivity of tungsten oxynitride

Journal of Materials Research ◽

10.1557/jmr.1998.0324 ◽

1998 ◽

Vol 13 (8) ◽

pp. 2321-2327 ◽

Cited By ~ 21

Author(s):

Toby E. Lucy ◽

Todd P. St. Clair ◽

S. Ted Oyama

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

X Ray Diffraction ◽

Heating Rates ◽

Continuous Transformation ◽

X Ray ◽

Synthesis Conditions ◽

Temperature Programmed ◽

Temperature Programmed Reaction

High surface area tungsten oxynitride has been prepared by the temperature programmed reaction (TPR) of WO3 with NH3. All samples were characterized by x-ray diffraction (XRD), nitrogen physisorption, CO chemisorption, and elemental analysis. Samples were prepared at different heating rates (β), and a Redhead analysis yielded an activation energy for nitridation of 109 kJ mol−1. A heating rate of 0.016 K s−1 gave optimal synthesis conditions. Solid state intermediates were studied by interrupting the temperature program at various stages. No distinct suboxide phases were found using XRD. The nitridation step was determined to be a continuous transformation from oxide to oxynitride. Surface area, CO uptake, and nitrogen weight % were all found to increase as the reaction progressed. Reactivity experiments showed reasonable hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) activity, but little hydrogenation (HYD) or hydrodesulfurization (HDS) activity.

Download Full-text

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

10.26434/chemrxiv.7770338.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Kailun Yang ◽

Recep Kas ◽

Wilson A. Smith

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Catalyst Layer ◽

Active Surface ◽

Active Surface Area ◽

High Concentration ◽

Copper Electrodes ◽

Surface Enhanced ◽

Local Current

This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO2 electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO2 electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO2 electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer.

Download Full-text

Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽

10.1039/c5nr02375k ◽

2015 ◽

Vol 7 (25) ◽

pp. 10974-10981 ◽

Cited By ~ 95

Author(s):

Xiulin Yang ◽

Ang-Yu Lu ◽

Yihan Zhu ◽

Shixiong Min ◽

Mohamed Nejib Hedhili ◽

...

Keyword(s):

Gas Phase ◽

Surface Area ◽

Hydrogen Evolution ◽

Hydrogen Generation ◽

High Surface ◽

High Surface Area ◽

Catalytic Efficiency ◽

Carbon Cloth ◽

Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

Download Full-text