scholarly journals Synthesis and catalytic properties of a novel copper- and manganese-substituted cerium dioxide for benzene remediation

2020 ◽  
pp. 174751982094588
Author(s):  
Jae Hwan Yang ◽  
Jeong Hyun You
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Environmental Remediation ◽  
Surface Defects ◽  
Superior Performance ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Transmission Electron

Catalysts based on inexpensive and abundant transition metals are necessary for effective environmental remediation. In this study, a series of CuMn-CeO2 catalysts is synthesized by a simple coprecipitation method. The properties of the as-prepared catalysts are characterized by X-ray diffraction, Brunauer–Emmett–Teller analysis, scanning electron microscopy–energy-dispersive spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The introduction of dopants results in rougher surfaces with greater surface areas and pore volumes as well as more surface defects. Furthermore, the dopant-added catalysts exhibit higher activities for benzene oxidation, as the temperature required for 90% benzene removal with Cu4Mn1-CeO2 (656 K) was 231 K lower than that required with CeO2. The superior performance of the dopant-added CeO2 catalyst is attributed to the generation of defect-rich surfaces due to the isomorphous substitution of Cu and Mn in the crystal lattice of CeO2.

Co(Ni)/MoS2 Nanostructured Catalysts for the Hydrodesulphurization of Dibenzothiophene

2008 ◽  
Vol 8 (12) ◽  
pp. 6437-6444 ◽  
Author(s):  
M. A. Albiter ◽  
R. Huirache-Acuña ◽  
F. Paraguay-Delgado ◽  
F. Zaera ◽  
G. Alonso-Núñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Nanostructured Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Surface Areas ◽  
Transmission Electron ◽  
Catalytic Test

In this study Co(Ni)/MoS2 unsupported nanocatalysts (nanorods and nanoribbons) were synthesized with Co(Ni)/(Co(Ni)+Mo)=0.3, 0.5 molar ratios for Co and Ni respectively. First the α-MoO3 nanostructures were impregnated with an aqueous solution of Co(Ni)Cl2·6H2O or Co(Ni)(NO3)2·6H2O, then were treated for 2 h at 473 K, and finally the precursors were activated under a H2S/H2 mixture (15% v/v H2S) by ramping the temperature from room temperature to 773 K and keeping it at that value for 2 h. The resulting materials were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, specific surface area and X-ray photoelectron spectroscopy, and tested as catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). It was found that these materials presented specific surface areas below 25 m2/g. The catalytic test showed that only when Co is added a promoter effect is observed compared with MoS2 unpromoted catalysts. Among the materials prepared, the Co/MoS2 catalyst made from cobalt chloride presented the highest catalytic activity (6.95 mol s−1 g−1catalyst) for the HDS of DBT. The selectivity for the latter indicated a clear preference for the direct desulphurization over the hydrogenating pathway.

Rapid Solvent-Free Melting Synthesis of Tungsten Nitrides with Lamellar, Solid Spherical Nanostructures at a Low Temperature

2012 ◽  
Vol 535-537 ◽  
pp. 314-318
Author(s):  
Wei Luo ◽  
Yan Tang ◽  
De Gang Ouyang ◽  
Bin Han ◽  
Ming Hui Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Solvent Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Transmission Electron ◽  
Tungsten Nitrides ◽  
Scanning Electron

A rapid solvent-free melting route has been successfully developed for the synthesis of tungsten nitrides with lamellar and solid spherical nanostructures which have considerably different surface areas (106.4 m2g-1contrast to 8.3 m2g-1) by the reaction of WCl6 and NaNH2 at 220 °C for 2-5 h directly, and it is found that the heat insulating property of reaction container plays important roles in the composition, phase, and morphologies of the nitrides. The products were analyzed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). Their thermal stability and surface area were measured by thermogravimetric analysis (TGA) and BET, respectively. Finally, the possible formation mechanism of tungsten nitrides with different morphologies was also investigated.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

scholarly journals Aluminum Nitride-Silicon Carbide Alloy Crystals Grown on SiC Substrates by Sublimation

2005 ◽  
Vol 10 ◽  
Author(s):  
Z. Gu ◽  
L. Du ◽  
J.H. Edgar ◽  
E.A. Payzant ◽  
L. Walker ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Original Source ◽  
X Ray ◽  
Alloy Crystal ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
Vapor Distribution ◽  
Uniform Composition

AlN-SiC alloy crystals, with a thickness greater than 500 µm, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 °C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8° or 3.68°) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlN-SiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had the wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 106 cm−2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.

scholarly journals Synthesis of Three-Dimensional Fe3O4/Graphene Aerogels for the Removal of Arsenic Ions from Water

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
3D Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Aerogels ◽  
Transmission Electron ◽  
Potential Applications ◽  
Removal Of Arsenic

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.

scholarly journals Microwave-assisted preparation of ZnS and ZnSe nanocrystals with different morphologies for photodegradation process of organic dyes

2019 ◽  
Author(s):  
Katarzyna Matras-Postolek ◽  
A. Zaba ◽  
S. Sovinska ◽  
D. Bogdal
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Organic Dyes ◽  
Zinc Sulphide ◽  
Conventional Heating ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Zinc sulphide (ZnS) and zinc selenide (ZnSe) and manganese-doped and un-doped with different morphologies from 1D do 3D microflowers were successfully fabricated in only a few minutes by solvothermal reactions under microwave irradiation. In order to compare the effect of microwave heating on the properties of obtained  nanocrystals, additionally the synthesis under conventional heating was conducted additionally in similar conditions. The obtained nanocrystals were systematically characterized in terms of structural and optical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The photocatalytic activity of ZnSe, ZnS, ZnS:Mn and ZnSe:Mn nanocrystals with different morphologies was evaluated by the degradation of methyl orange (MO) and Rhodamine 6G (R6G), respectively. The results show that Mn doped NCs samples had higher coefficient of degradation of organic dyes under ultraviolet irradiation (UV).

Synthesis and characterization of homogeneous lead-substituted tin oxide with the (110) face of rutile structure

2000 ◽  
Vol 15 (10) ◽  
pp. 2076-2079
Author(s):  
Chika Nozaki ◽  
Takashi Yamada ◽  
Kenji Tabata ◽  
Eiji Suzuki
Keyword(s):  
Electron Microscopy ◽  
Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Synthesis of a rutile-type lead-substituted tin oxide with (110) face was investigated. The characterization was performed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The homogeneous rutile-type lead-substituted tin oxide was obtained until 4.1 mol% of tin was substituted with lead. The surface of obtained oxide had a homogeneously lead-substituted (110) face.

Ag2O/ZnO Heterostructures with Enhanced Photocatalytic Activity

2021 ◽  
Vol 1035 ◽  
pp. 1043-1049
Author(s):  
Di Xiang ◽  
Chang Long Shao
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Environmental Remediation ◽  
Organic Dyes ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
P Type

A simple route has been developed for the synthesis of Ag2O/ZnO heterostructures and the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectroscopy analysis. Considering the porous structure of Ag2O/ZnO, the photocatalytic degradation for the organic dyes, such as eosin red (ER), methyl orange (MO), methylene blue (MB) and rhodamine B (RhB), under visible light irradiation was investigated in detail. Noticeably, Ag2O/ZnO just took 40 min to degrade 96 % MB. The rate of degradation using the Ag2O/ZnO heterostructures was 2.3 times faster than that of the bare porous ZnO nanospheres under visible light irradiation due to that the recombination of the photogenerated charge was inhibited greatly in the p-type Ag2O and n-type ZnO semiconductor. So the Ag2O/ZnO heterostuctures showed the potential application on environmental remediation.

scholarly journals Biomass-Derived Activated Carbon as a Catalyst for the Effective Degradation of Rhodamine B dye

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
High Specific Surface Area ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.

scholarly journals Solvent-Tuned Synthesis of Mesoporous Nickel Cobaltite Nanostructures and Their Catalytic Properties

2019 ◽  
Vol 9 (6) ◽  
pp. 1100 ◽  
Author(s):  
Xiangfeng Guan ◽  
Peihui Luo ◽  
Yunlong Yu ◽  
Xiaoyan Li ◽  
Dagui Chen
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Transmission Electron ◽  
Nickel Cobaltite ◽  
Solvent Type ◽  
Bet Method ◽  
Mesoporous Nico2o4

In this paper, we prepared mesoporous nickel cobaltite (NiCo2O4) nanostructures with multi-morphologies by simple solvothermal and subsequent heat treatment. By adjusting the solvent type, mesoporous NiCo2O4 nanoparticles, nanorods, nanowires, and microspheres were easily prepared. The as-prepared products were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) method. Furthermore, the catalytic activities towards the thermal decomposition of ammonium perchlorate (AP) of as-prepared NiCo2O4 nanostructures were investigated.

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