Higher Alcohols Synthesis from CO2 Hydrogenation over K2O-Modified CuZnFeZrO2 Catalysts

2013 ◽  
Vol 827 ◽  
pp. 20-24 ◽  
Author(s):  
Wei Guo ◽  
Wen Gui Gao ◽  
Hua Wang ◽  
Jun Jie Tian
Keyword(s):  
Space Time ◽  
Precipitation Method ◽  
Higher Alcohols ◽  
X Ray Diffraction ◽  
Time Space ◽  
Fe Content ◽  
Higher Alcohols Synthesis ◽  
Temperature Programmed ◽  
Space Time Yield ◽  
Co Precipitation

The CuZnFeZrO2 catalysts were synthesized by co-precipitation method.,and then used to synthesize different content of K2O modified CuZnFeZrO2 catalysts by deposition-precipitation method.Hydrogenation of CO2 to higher alcohols over (K2O)x/CuZnFeZrO2 catalysts were investigated at 523 K,3.0 MPa and 3000 h-1.These catalysts were characterized by X-ray diffraction (XRD),temperature programmed reduction of H2 (H2-TPR),and temperature-programmed desorption of CO2 (CO2-TPD).The results showed the addition of an appropriate amount of Potassium to the CuZnZrO2 catalysts improved catalytic activity ,the space time yield (STY) and C2+OH selectivity. When the Fe content is 5% best, at this time the space time yield of selectivity and alcohol of C2+ alcohol reaches the maximum value, this time space and time conversion rate is 0.32g/ml·h.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

scholarly journals Mechanochemically synthesized LiAlOx catalyst for aqueous aldol condensation of furfural with acetone

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
L. N. Stepanova ◽  
R. M. Mironenko ◽  
O. B. Belskaya ◽  
V. A. Likholobov
Keyword(s):  
Mixed Oxide ◽  
Aldol Condensation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Centripetal Acceleration ◽  
Oh Groups ◽  
Short Period ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Double Hydroxides

AbstractIn the present study, the mechanochemical method is proposed for synthesis of LiAl-layered double hydroxides (LDHs). This method is eco-friendly and allows obtaining LiAl-LDH under relatively mild conditions (centripetal acceleration of milling bodies 300 m s-2) and in a short period of time (15 minutes). The structures of as-prepared LiAl-LDH, LiAl-mixed oxide (calcined LDH) and “activated” LiAl-LDH obtained after rehydration of the corresponding mixed oxide were confirmed by X-ray diffraction. The basicity of LiAlOx was measured by temperature-programmed desorption of CO2 and double isotherm technique. According to data obtained, LiAl-mixed oxide has a significant higher carbon dioxide adsorption capacity compared to MgAlmixed oxides prepared by conventional co-precipitation method. This indicates a large amount of basic surface sites with different strength (strong, medium and weak) for Li-containing systems. The formation of “activated” LiAl-LDH having Bronsted basic sites (OH groups in the interlayer space) provides an increased catalytic activity of LiAlOx in the reaction of aqueous-phase aldol condensation between furfural and acetone.

scholarly journals Influence of Cr/Zr Ratio on Activity of Cr–Zr Oxide Catalysts in Non-Oxidative Propane Dehydrogenation

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1435
Author(s):  
Alexander Zubkov ◽  
Tatiana Bugrova ◽  
Mikhail Salaev ◽  
Grigory Mamontov
Keyword(s):  
Oxide Catalysts ◽  
Propane Dehydrogenation ◽  
Precipitation Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Mixed Oxide Catalysts ◽  
Uv Visible ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

Two series of chromium–zirconium mixed oxide catalysts with different Cr/Zr molar ratio are prepared by co-precipitation method. Porous structure of the catalysts is studied by low-temperature N2 adsorption–desorption. Phase composition and chromium states in the catalysts are characterized by X-ray diffraction (XRD), UV-visible spectroscopy, and temperature-programmed reduction with hydrogen (TPR-H2). The mixed catalysts are tested in non-oxidative dehydrogenation of propane at 550 °C. The catalysts synthesized without ageing of precipitate show higher activity in propane dehydrogenation due to the higher content of reducible Cr+5/+6 species due to its stabilization on the ZrO2 surface.

Pd-Only Catalyst Modified by BaO with Co- Precipitation and Impregnation Methods towards the Methanol Fuel Emission Control

2012 ◽  
Vol 581-582 ◽  
pp. 313-316
Author(s):  
Xue Qiao Zhang ◽  
Zhi Xiang Ye ◽  
Cheng Hua Xu ◽  
Ming Zhao ◽  
Yao Qiang Chen
Keyword(s):  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Palladium Catalysts ◽  
Active Species ◽  
Precipitation Method ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Co Precipitation

Barium oxide was introduced to modify Palladium catalysts supported on CeO2–ZrO2-La2O3-Al2O3 (CZLA) by impregnation and co-precipitation. methods. Various techniques, including X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS), were employed to characterize the physicochemical properties of BaO-modified Pd-only catalyst. Catalytic activity for methanol, CO, C3H8 and NO conversions showed that BaO-modified catalyst prepared by impregnation method exhibited the best performance for methanol, C3H8 and NO removals, while the catalyst prepared by co-precipitation method was in favor of CO oxidation. Combined with the results of XRD, H2-TPR and XPS, it is concluded that the co-existence of PdO and Pd-O-Ce active species by impregnation played an important role in the methanol, C3H8 and NO removals, while the higher dispersion of palladium and improved reducibility were mostly favorable to the CO oxidation. The conversion of NO was co-effected by tow active species and the formation of Ba2AlLaO5 mixed oxide.

scholarly journals Effect of Fe and Mn Substitution in LaNiO3 on Exsolution, Activity, and Stability for Methane Dry Reforming

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 27 ◽  
Author(s):  
Eswaravara Prasadarao Komarala ◽  
Ilia Komissarov ◽  
Brian A. Rosen
Keyword(s):  
Dry Reforming ◽  
Phase Changes ◽  
Carbon Accumulation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Methane Dry Reforming ◽  
Transmission Electron ◽  
Fe And Mn ◽  
Temperature Programmed ◽  
Co Precipitation

Perovskites LaNi0.8Fe0.2O3 and LaNi0.8Mn0.2O3 were synthesized using the co-precipitation method by substituting 20 mol.% of the Ni-site with Fe and Mn, respectively. Temperature programmed reduction (TPR) showed that the exsolution process in the Fe- and Mn-substituted perovskites followed a two-step and three-step reduction pathway, respectively. Once exsolved, the catalysts were found to be able to regenerate the original perovskite when exposed to an oxygen environment but with different crystallographic properties. The catalytic activity for both materials after exsolution was measured for the methane dry reforming (DRM) reaction at 650 °C and 800 °C. Catalyst resistance against nickel agglomeration, unwanted phase changes, and carbon accumulation during DRM were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The presence Fe alloying in the catalyst particles after exsolution from LaNi0.8Fe0.2O3 led to a lower methane conversion compared to the catalyst derived from LaNi0.8Mn0.2O3 where no alloying occurred.

Effect of Gallium Loading on Reducibility and Dispersion of Copper-Based Catalyst

2015 ◽  
Vol 659 ◽  
pp. 211-215
Author(s):  
Parncheewa Udomsap ◽  
Somsak Supasitmongkol
Keyword(s):  
Copper Oxide ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Reduction Peak ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Copper Phase ◽  
Temperature Programmed ◽  
Co Precipitation

The effect of gallium-promoted copper-based catalysts has been investigated in connection with the characteristic of the active copper phase. CuO-ZnO-Ga2O3catalysts with different gallium loadings were prepared using oxalate co-precipitation method. The effects of gallium loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR). The dispersion and metal area of copper were also determined by dissociative nitrous (N2O) adsorption technique conducted on a metal dispersion analyzer (BELCAT). The TPR profiles showed that the presence of two different reduction regions in the CuO-ZnO catalysts can be attributed to the reduction of highly dispersed copper oxide species (reduced at 246 °C) and bulk-like CuO (reduced at above 390 °C). By contrast, the only low-temperature reduction peak was presented in the TPR profiles after the Ga2O3loading was higher than 4 wt%. With the same molar ratio (Cu/Zn = 2:1), the reducibility of CuO-ZnO-Ga2O3was found to be more facile than CuO-ZnO due to the lower copper oxide crystallite sizes of gallium-promoted catalysts. Higher Ga2O3loadings resulted in an increase in both copper dispersion and metal surface area of all the catalysts studied in good agreement with the reduction behaviors in the TPR profiles, although all the gallium-promoted catalysts were slightly different for the reducibility.

The Reduction Properties of Hexa Aluminates Substituted by Different Metal Ions for Denitrification System

2013 ◽  
Vol 734-737 ◽  
pp. 2364-2368
Author(s):  
Xiao Guang Ren ◽  
Fu Xia Li ◽  
Peng Li ◽  
Wei Hou
Keyword(s):  
Metal Ions ◽  
Surface Area ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Co Precipitation

In this study, the hexaaluminate catalyst SrMnMAl10O19-δ（M= Cd、Co、Cu 、Fe、Ni、Zn、Zr、Cr and Y）and SrMnFexAl11-xO19-δ(x=1, 2, 4, 6, 8)have been prepared by co-precipitation method. The catalysts were characterized by powder X-ray diffraction (XRD), surface area (BET), hydrogen temperature programmed reduction (H2-TPR). The reduction catalyst properties of hexaaluminate for deNOx were evaluated by using devices of micro-evaluation. The results showed that the CO could remove NOx very well. The hexaaluminate not only have a good catalytic performance, but also can form a complete crystal calcined at 1200 °C for 4 h.

The Influence of Zn/Zr Ratios on CuO-ZnO-ZrO2 Catalysts for Methanol Synthesis from CO2 Hydrogenation

2014 ◽  
Vol 941-944 ◽  
pp. 425-429
Author(s):  
Yu Hao Wang ◽  
Wen Gui Gao ◽  
Yan E Zheng ◽  
Hua Wang
Keyword(s):  
Methanol Synthesis ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
Metallic Oxide ◽  
X Ray ◽  
Catalytic Activities ◽  
Reactive N ◽  
Temperature Programmed ◽  
Co Precipitation

A series of CuO–ZnO–ZrO2(CZZ) catalysts with different Zn/Zr ratios were successfully prepared by the co-precipitation method and characterized by the techniques of X-ray diffraction (XRD), N2adsorption, reactive N2O adsorption, H2temperature-programmed reduction (H2-TPR). The catalytic activities of the catalysts were tested for methanol synthesis from CO2hydrogenation. It was found that the increasing of the Zn/Zr ratio could lead to the increase of the crystallite size of metallic oxide. When the amount of ZnO ranged from 20% to 80%, the CZZ catalysts exhibited a better activity. It revealed that both Zn and Zr were important parameter for Cu-based catalysts, which were interacted with each other.

Preparation and Characterization of a New Type of Magnetic Polymer Micro Spheres

2011 ◽  
Vol 80-81 ◽  
pp. 405-408
Author(s):  
Li Li Zhang ◽  
Hong Wei Zhang ◽  
Xiang Hua Yao ◽  
Can Bang Zhang ◽  
Jia Jin Tian ◽  
...  
Keyword(s):  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Fe Content ◽  
New Type ◽  
Co Precipitation ◽  
Micro Morphology ◽  
Paramagnetic Properties

A new type of magnetic polymer microspheres with super paramagnetic properties were prepared by a co-precipitation method. Atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscopy (SEM) were used to analyze Fe content, micro morphology, particle size and phase structure of the products. Results indicate that the content of Fe in the microspheres is up to 5.25 *105ug/g. The main phase of the product is Fe3O4. The average particle sizes of the products are ~30nm.

Promoting Effect of Cobalt Addition on Higher Alcohols Synthesis over Copper-Based Catalysts

2012 ◽  
Vol 550-553 ◽  
pp. 270-275 ◽  
Author(s):  
Jian Guo Liu ◽  
Ming Yue Ding ◽  
Tie Jun Wang ◽  
Long Long Ma
Keyword(s):  
Fixed Bed ◽  
Product Distribution ◽  
Space Time ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Higher Alcohols ◽  
Promoting Effect ◽  
Higher Alcohols Synthesis ◽  
Co Concentration ◽  
Space Time Yield

The textural properties and microstructures of Co-modified Cu-based catalysts were investigated by N2 physisorption, X-ray diffraction (XRD), temperature-programmed reduction/desorption of hydrogen (H2-TPR/TPD) and scanning electron microscopy (SEM). Higher alcohols synthesis (HAS) was performed in a fixed bed reactor. The characterization results indicated that incorporation of cobalt in the Cu/γ-Al2O3 catalyst promoted the formation of CuCo2O4 crystallites, causing the decrease in BET surface area and pore volume. The gradual increase of CuCo2O4 concentration enhanced the adsorption of hydrogen on the surface layers, facilitating the formation of the well dispersed bimetal Cu-Co sites. In the HAS reaction, the catalytic activity of CO hydrogenation and space time yield of total alcohols presented an increasing trend with the increase in Co concentration. As the ratio of Co/Cu increased to 1, the catalyst produced the space time yield of 0.38 g.ml-1.h-1 and the selectivity of 65% for total alcohols, respectively. Moreover, higher Co concentration facilitated the product distribution shifting towards C2+OH.

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