Elucidating the structure, redox properties and active entities of high-temperature thermal aged CuOx-CeO2 catalysts for CO-PROX

2021 ◽  
Author(s):  
Zhihuan Qiu ◽  
Xiaolin Guo ◽  
Jianxin Mao ◽  
Renxian Zhou
Keyword(s):  
High Temperature ◽  
Rietveld Refinement ◽  
Copper Content ◽  
Redox Properties ◽  
Coprecipitation Method ◽  
Desorption Isotherm ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Adsorption Desorption

CuOx-CeO2 catalysts with different copper content are synthesized via a coprecipitation method and thermal treated at 700 oC. Various characterization techniques including X-ray diffraction (XRD) Rietveld refinement, N2 adsorption-desorption isotherm,...

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

Comparison of TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 Hybrid Catalysts in Characteristics and Photodegradation of Tetramethylammonium

2010 ◽  
Vol 93-94 ◽  
pp. 22-26 ◽  
Author(s):  
Surachai Artkla ◽  
Won Yong Choi ◽  
Jatuporn Wittayakun
Keyword(s):  
Irradiation Time ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Adsorption Desorption ◽  
Two Hybrid ◽  
Mcm 41

This work compared properties and catalytic performance of two hybrid photocatalysts, TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 prepared by loading nanoparticles of TiO2 (10 wt.%) on MCM-41 synthesized with rice husk silica and tetraethyl orthosilicate respectively. The supports and catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy and zeta potential. The photocatalytic activities of the TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 for the degradation of tetramethylammonium (TMA) in aqueous slurry were similar with a complete conversion after irradiation time of 90 min at pH 7.

The Application of Mesoporous ZSM-5 Zeolite in the ULSD Catalysts

2020 ◽  
Vol 4 (4) ◽  
pp. 1-3
Author(s):  
Liu L
Keyword(s):  
Catalytic Performance ◽  
Nitrogen Compounds ◽  
In Situ Ftir ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Acidic Sites ◽  
Adsorption Desorption ◽  
Al2o3 Catalyst

The mesoporous ZSM-5 zeolite containing MoCoP/Al2O3 catalyst (C12-ZSM5) with the mixture of Al2O3 and mesoporous ZSM- 5 zeolite as carrier was synthesized. The catalytic performance of C12-ZSM5 catalyst was evaluated by the hydrodesulfurization (HDS) of different diesel feedstock. The carriers and catalysts were characterized by N2 adsorption-desorption, pyridine-FTIR, X-ray diffraction (XRD) and CO in-situ FTIR (CO-FTIR) techniques. Results showed that mesoporous ZSM-5 can improve the acidity of the catalyst and increase the number of MoCoS active phases. The C12-ZSM5 catalyst had low HDS and HDN activity, because the acidic sites of mesoporous ZSM-5 were easily occupied by nitrogen compounds. The HDS activity of C12-ZSM5 catalyst was fully exploited by using graded packing technology, the sulfur content of product oil was 5.9 ng/μL. The relative HDS activity of C12-ZSM5 catalyst is 1.47 times that of FHUDS-8 catalyst.

Synthesis, Thermal and X-Ray Investigations of the High-Temperature Phase of Copper(I) Cyanide

2003 ◽  
Vol 58 (1) ◽  
pp. 155-158 ◽  
Author(s):  
Olaf Reckeweg ◽  
Cora Lind ◽  
Arndt Simon ◽  
J. Salvo
Keyword(s):  
High Temperature ◽  
Ir Spectroscopy ◽  
Chemical Analysis ◽  
Rietveld Refinement ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray

Abstract CuCN was investigated by chemical analysis, IR spectroscopy and powder X-ray diffraction. A high-temperature phase of CuCN was identified and structurally characterized by Rietveld refinement. HT-CuCN is isotypic to AgCN (R3m (No. 166), Z = 3, a = 597.109(8), c = 484.33(5) pm, Cu (3a), C/N (6c), z = 0.3915(10) at 77 K) with head-tail disorder of the cyanide anions.

Biosorption of crystal violet dye using inactive biomass of the fungus Diaporthe schini

2019 ◽  
Vol 79 (4) ◽  
pp. 709-717 ◽  
Author(s):  
Patrícia Grassi ◽  
Caroline Reis ◽  
Fernanda C. Drumm ◽  
Jordana Georgin ◽  
Denise Tonato ◽  
...  
Keyword(s):  
Crystal Violet ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
Biosorption Capacity ◽  
X Ray ◽  
Crystal Violet Dye ◽  
Endothermic Process ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Scanning Electron

Abstract An inactive biomass of a new fungus recently discovered, Diaporthe schini, was evaluated for the biosorption of crystal violet (CV) in simulated textile effluents. The characterization assays were performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and N2 adsorption/desorption isotherms. The influences of pH and biosorbent dosage on the biosorption capacity were evaluated. Kinetics, equilibrium and thermodynamic studies were also carried out. Characterization techniques showed an amorphous biosorbent, with a rough surface containing irregular particles and surface area of 6.5 m2 g−1. The most adequate values of pH and biosorbent dosage were 7.5 and 0.4 g L−1, respectively. The Elovich kinetic model and the Sips equilibrium model were suitable to fit the experimental data. The biosorption capacity increased with temperature, reaching a maximum biosorption capacity of 642.3 mg g−1 at 328 K. The biosorption was a spontaneous and endothermic process. Diaporthe schini inactive biomass was an interesting biosorbent to treat colored effluents, presenting efficiency of 87% in the decolorization of a simulated dye house effluent.

Deactivation Behavior of CuXCe1-XO2-X/SBA-15/Cordierite Monolithic Catalysts for Catalytic Combustion of CO

2012 ◽  
Vol 550-553 ◽  
pp. 383-387 ◽  
Author(s):  
Fu Zhen Zhao ◽  
Wen Qiang Liang ◽  
Sheng Bin Ling ◽  
Yu Qing Wu ◽  
Ai Qing Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Monolithic Catalysts ◽  
Adsorption Desorption

A series of CuxCe1-xO2-x/SBA-15/cordierite (x = 0-1) catalysts were prepared. The activity of the catalysts for CO combustion was evaluated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and X-ray photoelectron spectroscopy (XPS). Deactivation behavior of the catalysts for the catalytic combustion of CO was investigated. The results show that all of the catalysts retained the SBA-15 mesoporous structure. It is proposed that deactivation of the catalysts is associated with the increase of the Cu+ and the decrease of the Cu2+ in the catalysts.

scholarly journals Synthesis of micro-mesopores flowerlike γ-Al2O3 nano-architectures

2014 ◽  
Vol 79 (8) ◽  
pp. 1007-1017 ◽  
Author(s):  
Mozaffar Abdollahifar ◽  
Reza Zamani ◽  
Ehsan Beiygie ◽  
Hosain Nekouei
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Total Pore Volume ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Adsorption Desorption

The micro-mesopores flowerlike ?-Al2O3 nano-architectures have been synthesized by thermal decomposition method using the synthesized AlOOH (boehmite) as precursor. After calcination at 500?C for 5 h, the obtained flowerlike ?-Al2O3 has similar structure like the AlOOH precursor. X-ray diffraction (XRD), FTIR, TG, FESEM and TEM techniques were used to characterize morphology and structure of the synthesized samples. The specific surface area (BET), pore volume and pore-size distribution of the products were determined by N2 adsorption-desorption measurements. The flowerlike ?-Al2O3 showed BET high specific surface area 148 m2 g-1 with total pore volume 0.59 cm3 g-1.

FIXED TRIANGLE IN Bi2-XPbXSr2CaCu2O8+Y AND Bi2-XPbXSr2Ca2Cu3O10+Y SYSTEMS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362015 ◽  
Author(s):  
C. Q. GUO ◽  
C. Y. ZHANG ◽  
S. J. HAO ◽  
W. T. JIN ◽  
H. ZHANG
Keyword(s):  
High Temperature ◽  
Rietveld Refinement ◽  
Chemical Bond ◽  
Rock Salt ◽  
Local Structure ◽  
High Temperature Superconductivity ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Close Relationship

The structural characteristics of Bi 2-x Pb x Sr 2 CaCu 2 O 8+y( Bi -2212) and Bi 2-x Pb x Sr 2 Ca 2 Cu 3 O 10+y( Bi -2223) with x changing from 0 to 0.8 were studied by X-ray diffraction and Rietveld refinement. By careful calculation of chemical bond lengths and angles, it is found that there exists a fixed triangle on the Cu–O planes in the two systems, and then makes the Cu–O planes stable. The fluctuations of this fixed triangle were investigated, and it is found that there is a close relationship between it and Tc's. In addition, we discussed the origin of this special local structure. It may be caused by the interaction between the perovskite block and the rock salt block in a unit cell, which may play an important role in the mechanism of high temperature superconductivity.

scholarly journals Effect of High Pressure on the Reducibility and Dispersion of the Active Phase of Fischer–Tropsch Catalysts

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1915 ◽  
Author(s):  
Simón Yunes ◽  
Miguel Ángel Vicente ◽  
Sophia A. Korili ◽  
Antonio Gil
Keyword(s):  
High Pressure ◽  
Physicochemical Characterization ◽  
Active Phase ◽  
Incipient Wetness Impregnation ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

The effect of high pressure on the reducibility and dispersion of oxides of Co and Fe supported on γ-Al2O3, SiO2, and TiO2 has been studied. The catalysts, having a nominal metal content of 10 wt.%, were prepared by incipient wetness impregnation of previously calcined supports. After drying at 60 °C for 6 h and calcination at 500 °C for 4 h, the catalysts were reduced by hydrogen at two pressures, 1 and 25 bar. The metal reduction was studied by temperature-programmed reduction up to 750 °C at the two pressures, and the metal dispersion was measured by CO chemisorption at 25 °C, obtaining values between 1% and 8%. The physicochemical characterization of these materials was completed by means of chemical analysis, X-ray diffraction, N2 adsorption-desorption at −196 °C and scanning electron microscopy. The high pressure lowered the reduction temperature of the metal oxides, improving their reducibility and dispersion. The metal reducibility increased from 42%, in the case of Fe/Al2O3 (1 bar), to 100%, in the case of Fe/TiO2 (25 bar).

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