The Effect of Support Pretreatment with Ammonia on Pd/SiO2 Catalyst

2018 ◽  
Vol 922 ◽  
pp. 125-129
Author(s):  
Ji Soo Kwon ◽  
Jae Ho Baek ◽  
Hak Sung Lee ◽  
Man Sig Lee
Keyword(s):  
Silanol Group ◽  
N2 Adsorption ◽  
Ammonia Water ◽  
Co Chemisorption ◽  
Silanol Groups ◽  
Pd Dispersion ◽  
Highly Dispersed ◽  
High Metal ◽  
Ft Ir ◽  
Effect Of Support

We have reported the effect of support pretreatment with ammonia on Pd/SiO2 catalyst in this study. SiO2 was pretreated with ammonia water to increase the Pd dispersion before the preparation of Pd/SiO2 catalysts. The effect of support pretreatment with ammonia on Pd/SiO2 catalyst was investigated by XRD, FT-IR, N2-adsorption and FE-TEM. The Pd supported on pretreated SiO2 were characterized by XRD, CO-chemisorption and FE-TEM. The pretreatment of SiO2 with ammonia water lead to decrease of silanol groups (Si-OH) up to temperature 200 °C. This decline of silanol groups on the SiO2 affects highly dispersed Pd/SiO2 as 6.52 %. The result showed that the decrease of silanol group on the SiO2 was favorable for the Pd dispersion. It is reason that absence of the silanol groups contribute to the high metal reducibility.

The Preparation of Highly Dispersed Pd/Gamma-Al2O3 Catalyst: The Relation of Attracting-Repelling Force and Pd Dispersion

2018 ◽  
Vol 922 ◽  
pp. 130-135
Author(s):  
Mi Yeon Byun ◽  
Ji Sun Kim ◽  
Jeong Wook Park ◽  
Dae Won Park ◽  
Man Sig Lee
Keyword(s):  
Particle Size ◽  
Surface Charge ◽  
Charge State ◽  
Precipitation Method ◽  
Co Chemisorption ◽  
Pd Dispersion ◽  
Highly Dispersed

The purpose of this study is to present the effect of attracting-repelling force on the dispersion and particle size of palladium (Pd) between Pd and γ-Al2O3. The Pd supported on γ-Al2O3 catalyst were prepared by deposition-precipitation method with two different ways. From the CO-Chemisorption results, Pd/γ-Al2O3 (R2-FM) catalyst has the highest Pd dispersion of 43.16%. The results showed that particle size and distribution of Pd influenced by the surface charge state of γ-Al2O3 support, indicating relation of attracting-repelling force between Pd precursor and γ-Al2O3 surface.

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.

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.

scholarly journals Friedel-Crafts Acylation of Furan: Development of A Green Process Using Chromium-exchanged Dodecatungstophosphoric Acid: Effect of Support, Mechanism and Kinetic Modelling

2021 ◽  
Author(s):  
Deepak S. Desai ◽  
Ganapati D. Yadav
Keyword(s):  
Acetic Anhydride ◽  
Kinetic Modelling ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Support Mechanism ◽  
Full Characterization ◽  
Prior Art ◽  
Acid Effect ◽  
Ft Ir ◽  
Effect Of Support

Abstract The Friedel-Crafts acylation of furan with acetic anhydride to produce 2-acyl furan is industrially important. With an aim of replacing the highly polluting process, it this study, supported but modified heteropoly acids were used. Metal exchanged dodecatungstophosphoric acid (DTP) was loaded on three different supports and its effect on acylation was evaluated. Thus, chromium exchanged DTP was supported on K-10, SiO2, and ZrO2 using the incipient wetness impregnation method. 20% w/w Cr0.66-DTP/K-10 having the best activity for the acylation of furan with acetic anhydride was chosen for full characterization and reaction kinetics. Under optimized condition, the catalyst to furan ratio was 9.6%, significantly less as per prior art, which gave 88% conversion with 100% selectivity. The prepared catalysts were characterized by sophisticated techniques, namely, XRD, FT-IR, SEM, NH3-TPD, TGA, and BET. The Eley-Rideal mechanism was found to fit the kinetic data. The activation energy was found to be 18.03 kcal/mol. The reaction is green and clean as no chlorinated chemicals, reagents, and catalysts were used.

Carbonaceous minerals as corrosion products on the surface of bottles

2020 ◽  
Vol 61 (6) ◽  
pp. 185-191
Author(s):  
A. Özcan ◽  
◽  
B. Arman ◽  
S. Demirli ◽  
M. Orhon
Keyword(s):  
Analytical Techniques ◽  
Test Methods ◽  
Critical Parameters ◽  
Humid Atmosphere ◽  
Silanol Groups ◽  
Annealing Conditions ◽  
Gel Layer ◽  
Colour Scale ◽  
Blue Solution ◽  
Ft Ir

During the corrosion process, as the ion exchange between the surface of the glass and the water progresses, the chemical structure of the surface changes and different structural layers are formed. These layers are characterised by various analytical techniques such as EPMA, XRD, FT-IR, TG-DTA and ICP-OES. Three carbonate mineral species namely calcite (CaCO3), shortite (Na2Ca2(CO3)3) and nyerereite (Na2Ca(CO3)2) have been identified at the outermost deposition layer. Critical parameters that affect the formation of the alkali depleted and silica enriched gel layer are investigated using some special test methods. Methylene blue solution reacts with the silanol groups of gel layer leaving a blue tint behind, the intensity of which varies with the extent of corrosion as the amount of silanol groups outcropped due to the increase of the porous structure area. A colour scale is developed to determine the level of corrosion and the results are correlated with the results of other known chemical analysis methods. The effect of annealing conditions on the chemical resistance of the surfaces and the role of the shape of the bottles on the water condensation at humid atmosphere are studied. The results of acid treatment and re-annealing of the corroded surfaces are described.

Preparation Crystalline Mesoporous Titania at Mild Conditions with Inorganic Titanium Precursors

2010 ◽  
Vol 113-116 ◽  
pp. 2053-2056
Author(s):  
Yan Wang ◽  
Rui Qing Liu ◽  
Ai Hua Wen ◽  
Xuan Dong Li
Keyword(s):  
Soxhlet Extraction ◽  
Temperature Treatment ◽  
Mesoporous Tio2 ◽  
High Temperature Treatment ◽  
Mesoporous Titania ◽  
N2 Adsorption ◽  
Mild Conditions ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Additive Reaction

In order to avoid the damage on mesostructure by the high temperature treatment, inorganic titanium species were used as the precursors for the preparation of mesoporous TiO2 of crystalline framework at mild conditions. The influences of the precursor, additive, reaction pH and temperature on phase and textural structures of the products were investigated. The samples were characterized by XRD, N2 adsorption/desorption, FT-IR and SEM. The results show that anatase mesoporous TiO2 with large surface area could be obtained without calcination with Ti(SO4)2 as precursor or TiCl4 when SO42- was added. And the template could be completely removed by Soxhlet extraction.

Preparation and Characterization of Supported H3PW12O40 and Supported Cesium-Substituted Dodecatungstophosphate

2012 ◽  
Vol 509 ◽  
pp. 321-327 ◽  
Author(s):  
Zi Li Liu ◽  
Cui Xia Xu ◽  
Qian Wen Dai ◽  
Chao Xiang ◽  
Jian Jie Zhang
Keyword(s):  
Solid Acid ◽  
Solid Acid Catalysts ◽  
Incipient Wetness Impregnation ◽  
Acid Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Dispersed ◽  
Probe Experiment ◽  
Ft Ir

Supported H3PW12O40 (HPW) and supported Cesium-Substituted dodecatungsto-phosphate are eco-friendly solid acid catalysts. A series of different loading H3PW12O40/SiO2 and HPW/diatomite were prepared by a typical incipient wetness impregnation of methanol, meanwhile SiO2 and diatomite supported Cs-salt catalysts were prepared via two-step impregnating method. The catalysts were investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the Keggin structure of HPW is intact in the SiO2-supported HPW and SiO2-supported CsHPW. HPW and CsHPW are highly dispersed in the SiO2 at the low loading, while the loading is more than 40% the catalyst grains increase and gather on the surface of the carrier. What's more, diatomite is not a suitable support. HPW and CsHPW have better distribution in the SiO2 than in the diatomite. The activity of catalyst was tested in probe experiment of the alkylation of thiopene (TH) with 1-hexene.

scholarly journals Influence of the addition of Pd and Cu to cobalt catalysts prepared by SMAI for F-T synthesis

2007 ◽  
Vol 5 (1) ◽  
pp. 144-155 ◽  
Author(s):  
Li-hua Yu ◽  
Shou-min Zhang ◽  
Xianzhi Guo ◽  
Da Wang ◽  
Shu-rong Wang ◽  
...  
Keyword(s):  
Metal Atom ◽  
Co Hydrogenation ◽  
Magnetic Measurements ◽  
Weight Ratio ◽  
Cobalt Catalysts ◽  
Metallic State ◽  
Fischer Tropsch ◽  
Superparamagnetic Behavior ◽  
Highly Dispersed ◽  
Ft Ir

AbstractThe Co-Pd/SiO2 and Co-Cu/SiO2 catalysts were prepared via solvated metal atom impregnation (SMAI) method and investigated for the Fischer-Tropsch (F-T) synthesis. The catalysts contained 5wt.% Co and a weight ratio of Pd (or Cu) to Co of 1/30. XPS indicated that Co, Pd and Cu were in metallic state. The results of XPS and magnetic measurements showed that Co and Pd (Cu) were alloyed. The Co particles on the catalysts were very highly dispersed and they displayed superparamagnetic behavior. FT-IR indicated that the electrons shifted from Cu and Pd to Co. Catalytic tests showed that CO hydrogenation rates followed the order Pd-Co > Cu-Co > Co.

Effect of Support on the Size and Composition of Highly Dispersed Pt–Sn Particles

2002 ◽  
Vol 211 (2) ◽  
pp. 335-346 ◽  
Author(s):  
L. Bednarova ◽  
C.E. Lyman ◽  
E. Rytter ◽  
A. Holmen
Keyword(s):  
Highly Dispersed ◽  
Effect Of Support

scholarly journals Catalytic Conversion of Cellulose to 5-hydroxymethylfurfural (5-HMF) Over Nano SO42--ZrO2 /MCM-41 Catalysts

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Pham Tung Son ◽  
Le Ha Giang ◽  
Nguyen Ba Manh ◽  
Pham Thi Thu Trang ◽  
Vu Quang Loi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Selectivity ◽  
Sol Gel ◽  
Catalyst System ◽  
Hydroxymethyl Furfural ◽  
Structure And Morphology ◽  
Highly Dispersed ◽  
Ft Ir ◽  
Mcm 41 ◽  
Medium Acidity

A zirconium catalyst system supported on MCM-41 (S-Z) with various weight components (4-20 wt.%) Was synthesized by the sol-gel method. Structure and Morphology Catalysts were characterized by X-RD, TEM, BET, FT-IR and TPD-NH3 methods. In this catalyst, ZrO2 is highly dispersed on the surface of MCM-41 capillaries. Catalytic activity and selectivity were evaluated by the effectiveness of mild hydrothermal decomposition of cellulose to 5-hydroxymethyl furfural (5-HMF). The results show that a catalyst with medium acidity exhibits a high selectivity of 5-HMF. Keywords: S-Zr/MCM-41 materials, sol-gel methods, cellulose, 5-HMF.

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