scholarly journals Performance of a Ni-Cu-Co/Al2O3 Catalyst on in-situ Hydrodeoxygenation of Bio-derived Phenol

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 952 ◽  
Author(s):  
Huiyuan Xue ◽  
Xingxing Gong ◽  
Jingjing Xu ◽  
Rongrong Hu
Keyword(s):  
Electron Microscope ◽  
Synergistic Effects ◽  
X Ray ◽  
Transmission Electron ◽  
Production Of Hydrogen ◽  
Good Potential ◽  
Temperature Programmed ◽  
Positive Effect ◽  
Al2o3 Catalyst

The in-situ hydrodeoxygenation of bio-derived phenol is an attractive routine for upgrading bio-oils. Herein, an active trimetallic Ni-Cu-Co/Al2O3 catalyst was prepared and applied in the in-situ hydrodeoxygenation of bio-derived phenol. Comparison with the monometallic Ni/Al2O3 catalyst and the bimetallic Ni-Co/Al2O3 and Ni-Cu/Al2O3 catalysts, the Ni-Cu-Co/Al2O3 catalyst exhibited the highest catalytic activity because of the formation of Ni-Cu-Co alloy on the catalyst characterized by using X-ray powder diffraction (XRD), temperature programmed reduction (TPR), N2 physisorption, scanning electron microscope (SEM), and transmission electron microscope (TEM). The phenol conversion of 100% and the cyclohexane yield of 98.3% could be achieved in the in-situ hydrodeoxygenation of phenol at 240 °C and 4 MPa N2 for 6 h. The synergistic effects of Ni with Cu and Co of the trimetallic Ni-Cu-Co/Al2O3 catalyst played a significant role in the in-situ hydrodeoxygenation process of phenol, which not only had a positive effect on the production of hydrogen but also owned an excellent hydrogenolysis activity to accelerate the conversion of cyclohexanol to cyclohexane. Furthermore, the catalyst also exhibited excellent recyclability and good potential for the upgrading of bio-oils.

scholarly journals Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1096
Author(s):  
Ligang Luo ◽  
Xiao Han ◽  
Qin Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Hydrogen Donor ◽  
Effect Of Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

scholarly journals Influence of Intercalation-Exfoliation-Reduction Technique towards the Physico-Chemical of VPO Catalysts

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Y. C. Wong ◽  
Y. H. Taufiq-Yap
Keyword(s):  
Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vpo Catalysts ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Vpo Catalyst ◽  
Temperature Programmed ◽  
Lower Temperature ◽  
Synthesized Materials

Four VPO catalysts were synthesized through intercalation and exfoliation in various alcohols and subsequent reduction of the exfoliated VOPO4sheets with various alcohols to produce VOHPO4⋅0.5H2O. The resulting VOHPO4⋅0.5H2O that undergoes the intercalation-exfoliation-reduction (IER) process will be further activated into VPO catalysts, and addition of 1 mole % Bi(NO3)3⋅5H2O in the first stage of this experiment has also being investigated. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and temperature-programmed reduction (TPR) in H2. Catalytic evaluation of the IER-treated and Bi-doped VPO catalysts was also studied on microreactor. The VPO catalyst produced through IER using 2-butanol and ethanol with addition of Bi, IERC(2Bu-Et)RBi1, gave the highest MA selectivity due to reactive O2−species released from the additional crystalline V5+phase formed by doping 1% bismuth as promoter (O2−-V5+pair) at relative lower temperature. Nevertheless, the VPO catalyst produced through IER using isobutanol, IERC(isoBu), gave the highest activity due to high amount of reactive O−species released from V4+phase (O−-V4+pair) whereby the IERC(isoBu) catalyst synthesized consists of high percentage of V4+(93 %).

Controlled Environment Specimen Transfer

2014 ◽  
Vol 20 (4) ◽  
pp. 1038-1045 ◽  
Author(s):  
Christian D. Damsgaard ◽  
Henny Zandbergen ◽  
Thomas W. Hansen ◽  
Ib Chorkendorff ◽  
Jakob B. Wagner
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Elevated Temperatures ◽  
Controlled Environment ◽  
Ambient Atmosphere ◽  
Air Exposure ◽  
X Ray ◽  
Environmental Transmission ◽  
Transmission Electron

AbstractSpecimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3 catalyst for methanol synthesis and a Co/Al2O3 catalyst for Fischer–Tropsch synthesis. Both systems are sensitive to ambient atmosphere as they will oxidize after relatively short air exposure. The Cu/ZnO/Al2O3 catalyst, was reduced in the in situ X-ray diffractometer set-up, and subsequently, successfully transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ transfer holder facilitates complimentary in situ experiments of the same specimen without changing the specimen state during transfer.

scholarly journals A rapid method of cryofixation of tissues in situ for ultracryomicrotomy.

1980 ◽  
Vol 28 (1) ◽  
pp. 47-51 ◽  
Author(s):  
S H Chang ◽  
W J Mergner ◽  
R E Pendergrass ◽  
R E Bulger ◽  
I K Berezesky ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Punch Biopsy ◽  
Sampling Device ◽  
X Ray ◽  
Cell Compartments ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Tissue Specimens

A device is described for the rapid freezing of tissue in situ by a punch biopsy approach using a specially designed cryogun with a highly thermal conductive specimen holder. The cryogun consists of a sampling device using a double, spring-loaded gun mechanism and a system of cryochambers. Ultrathin freeze-dried sections cut from samples obtained with this cryogun are relatively free of artifacts and have few ice crystals. Organelles are seen by natural contrast when cryosections of approximately 1000 A are observed with a transmission electron microscope or in the transmission mode of a scanning electron microscope. The construction of the cryogun is described along with a method of obtaining improved, ultrafast cryofixation of tissue specimens. The reliability of obtaining x-ray microanalysis measurements of diffusible ions where movement within cell compartments has been retained is discussed.

X-ray Energy-Dispersive Spectrometry During In Situ Liquid Cell Studies Using an Analytical Electron Microscope

2014 ◽  
Vol 20 (2) ◽  
pp. 323-329 ◽  
Author(s):  
Nestor J. Zaluzec ◽  
M. Grace Burke ◽  
Sarah J. Haigh ◽  
Matthew A. Kulzick
Keyword(s):  
Electron Microscope ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Liquid Cell

AbstractThe use of analytical spectroscopies during scanning/transmission electron microscope (S/TEM) investigations of micro- and nano-scale structures has become a routine technique in the arsenal of tools available to today’s materials researchers. Essential to implementation and successful application of spectroscopy to characterization is the integration of numerous technologies, which include electron optics, specimen holders, and associated detectors. While this combination has been achieved in many instrument configurations, the integration of X-ray energy-dispersive spectroscopy and in situ liquid environmental cells in the S/TEM has to date been elusive. In this work we present the successful incorporation/modifications to a system that achieves this functionality for analytical electron microscopy.

Transformation of mackinawite to greigite; an in situ X-ray powder diffraction and transmission electron microscope study

1997 ◽  
Vol 82 (3-4) ◽  
pp. 302-309 ◽  
Author(s):  
Alistair R. Lennie ◽  
Simon A. T. Redfern ◽  
Pamela E. Champness ◽  
Chris P. Stoddart ◽  
Paul F. Schofield ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Powder Diffraction ◽  
Transmission Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
X Ray ◽  
Transmission Electron ◽  
Transmission Electron Microscope Study

IN SITU ASSEMBLY OF ZnS NANOFIBERS WITH HIGHLY ORDERED LAMELLAR MESOSTRUCTURE

2006 ◽  
Vol 05 (02n03) ◽  
pp. 245-251 ◽  
Author(s):  
JUNPING LI ◽  
YAO XU ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Electron Microscope ◽  
Thermal Analyses ◽  
Blue Shift ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible

ZnS nanofibers with lamellar mesostructure could be built up from in situ generated ZnS precursors via hydrothermal routes using neutral n-alkylamines as structure-directing template and ethylene diamine tetraacetic acid (EDTA) as stabilizer. The morphology and structure of the obtained products were thoroughly investigated via scanning electron microscope (SEM), energy dispersive analysis of X-rays (EDX), transmission electron microscope (TEM), X-ray powder diffraction (XRD) and thermal analyses. HRTEM and XRD results revealed that the so-produced nanofibers were lamellar mesostructure and its framework was built of crystalline wurtzite ZnS . It was also found that the distance between the layers was proportional to the chain length of the alkylamine. The UV-visible absorption spectrum showed that the nanofibers exhibited strong quantum-confined effect with a blue shift in the band gap. Finally, a probable mechanism for the assembly of the nanofibers was also proposed.

scholarly journals Characterization of Highly Dispersed Rod- and Particle-Shaped CuFe19Ox Catalysts and Their Shape Effects on WGS

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 635
Author(s):  
Lingjuan Ma ◽  
Dawei Han ◽  
Hongbin Ma ◽  
Longgang Liu ◽  
Huichao Guo
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Transmission Electron ◽  
Highly Dispersed ◽  
Shape Effects ◽  
Temperature Programmed ◽  
Water Gas

Highly dispersed CuFe19Ox catalysts with different shapes were prepared and further characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and in-situ XRD. XRD and TEM results showed that the synthesized CuFe19Ox nanoparticles consisted of CuO and Fe2O3, while CuFe19Ox nanorods consisted of CuFe2O4 and Fe2O3. The reduction properties of CuFe19Ox samples were finely studied by H2-TPR, and the phase composition was identified by in-situ XPS, HR-TEM, and surface TPR (s-TPR). In-situ X-ray photoelectroscopy (XPS) indicated that the metallic Cu and Fe3O4 were the main species after reduction. Moreover, s-TPR studies showed that the reduction performance of copper was significantly affected by the shapes of the Fe3O4 supports. Low-temperature water gas shift (LT-WGS) was chosen to characterize the Cu species on the surface. It was found that reduced CuFe19Ox nanorods had no activity. On the contrary, reduced CuFe19Ox particles showed higher initial WGS activity, where the active Cu0 should originate from the reduction of Cu2O at lower temperatures, as confirmed by the s-TPR profiles.

scholarly journals Liquid exfoliated MoS2 Sheet coupled with Conductive Polyaniline for Gas Sensor

2021 ◽  
Author(s):  
Hemalatha Parangusan ◽  
Jolly Bhadra ◽  
Razen Al-Qudah ◽  
Hibballa Elgurashi ◽  
Marwa Abdelhakem ◽  
...  
Keyword(s):  
Electron Microscope ◽  
In Situ Polymerization ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Mos2 Nanosheet ◽  
Conductive Polyaniline ◽  
Polymerization Method

Polyaniline (PANI)/MoS2 composites with porous microspheres were prepared by a hydrothermal and in situ polymerization method. The structural, optical, and morphological properties were characterized by X-ray powder diffraction, FTIR, scanning electron microscope, transmission electron microscope. The XRD results confirmed that the PANI/MoS2 composite was formed. Morphological characterization reveals that the successful formation of few to multilayered MoS2 nanosheet intercalated with the PANI nanoparticles.

In Situ Tem Study of Amorphous to Crystalline Transformation in R-Fe-B Ribbons

1991 ◽  
Vol 232 ◽  
Author(s):  
Y. J. Zhang ◽  
Y. Z. Wang ◽  
G. C. Hadjipanayis
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Building Blocks ◽  
In Situ Tem ◽  
Local Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unit Structure ◽  
Transmission Electron

ABSTRACTThe amorphous-crystalline transformation in R-Fe-B ribbons was studied in situ in a transmission electron microscope (TEM) and with X-ray diffraction. Metastable phases of α-Fe(R) and Fe3B were found to form during crystallization before the final R2Fe14B phase is formed. The Fe3B phase is believed to be important for the formation of the 2:14:1 phase because its “local unit structure” is one of the basic building blocks in the 2:14:1 unit cell.

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