Physicochemical Characteristics of the Birnessite and Todorokite Synthesized Using Various Methods

The synthesis methods used to produce todorokite (10 Å manganate, OMS-1) and birnessite (7 Å manganate), which are abundant in marine manganese nodules, have been studied to confirm whether pure mineral phases can be obtained and to compare their physicochemical characteristics. The physicochemical characteristics of todorokite and its precursor Na–birnessite can vary widely based on the precursors used during their synthesis. Birnessite can be synthesized via three mechanisms, i.e., the oxidation of Mn2+, a redox reaction between Mn2+ and MnO4−, or the reduction of MnO4−. Herein, four precursors are used to synthesize birnessite using different methods before being transformed into todorokite. The characteristics of the birnessite and todorokite synthesized using different methods are investigated via X-ray diffraction (XRD), chemical analysis, Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (SEM). Based on the method used, birnessite and todorokite exhibit distinct physicochemical features, including crystallinity, crystal structure, specific surface area, oxidation state of manganese, thermal stability, and morphology. Thus, the characteristics of birnessite and todorokite are closely correlated, indicating the importance of designing suitable methods to synthesize them for specific applications.

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Study on Hydrogenation Performance of Oil-Soluble Molybdenum Catalyst in Coal-Oil Co-Processing

10.21203/rs.3.rs-1216417/v1 ◽

2022 ◽

Author(s):

Guangyao Wang ◽

Xiqian Wang ◽

Yuan Zhao

Keyword(s):

Crystal Structure ◽

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Heavy Fraction ◽

X Ray Diffraction ◽

Molybdenum Catalyst ◽

X Ray ◽

Transmission Electron ◽

Novel Method ◽

Scanning Electron

Abstract An oil-soluble molybdenum catalyst was synthesized by a simple and novel method and studied for hydrogenation in coal-oil co-processing. The catalyst was characterized by infrared spectrum (IR), thermogravimetry (TG), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology and crystal structure of catalyst was characterized with scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The catalyst can be considered as a precursor that can be converted into active MoS2 components through thermal decomposition and sulfidation. The hydrogenation experiment was carried out by the model reactants of tetradecane and 2-methylnaphthalene with a change of reaction (405℃-445℃) temperature and concentrations of molybdenum catalyst (Mo conc. 0.6-10 mg/g), and results showed that the delightly hydrogenation function of catalyst is to improve the saturation of aromatic ring. The most abundant stacking numbers of decomposed catalyst were 2 and 3, accounting for 53% of all catalyst microcrystalline units. The rapid hydrogenation stage and the significant decrease of feed heavy fraction in co-processing experiment provided the evidence that the hydrogenation performance of the synthesized catalyst is remarkable in coal-oil co-processing.

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Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽

10.3390/coatings11080937 ◽

2021 ◽

Vol 11 (8) ◽

pp. 937

Author(s):

Yingying Hu ◽

Md Rasadujjaman ◽

Yanrong Wang ◽

Jing Zhang ◽

Jiang Yan ◽

...

Keyword(s):

Crystal Structure ◽

Optical Properties ◽

Photoelectron Spectroscopy ◽

Crystal Size ◽

Silicon Substrates ◽

X Ray Diffraction ◽

Dc Magnetron Sputtering ◽

Flow Rates ◽

X Ray ◽

N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

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Biodiesel Production on Monometallic Pt, Pd, Ru, and Ag Catalysts Supported on Natural Zeolite

Materials ◽

10.3390/ma14010048 ◽

2020 ◽

Vol 14 (1) ◽

pp. 48

Author(s):

Pawel Mierczynski ◽

Magdalena Mosińska ◽

Lukasz Szkudlarek ◽

Karolina Chalupka ◽

Misa Tatsuzawa ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Natural Zeolite ◽

Noble Metals ◽

Methyl Esters ◽

Physicochemical Characteristics ◽

Biodiesel Production ◽

X Ray Diffraction ◽

X Ray ◽

Yield Values ◽

Temperature Programmed

Biodiesel production from rapeseed oil and methanol via transesterification reaction facilitated by various monometallic catalyst supported on natural zeolite (NZ) was investigated. The physicochemical characteristics of the synthesized catalysts were studied by X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), temperature-programmed-reduction in hydrogen (H2-TPR), temperature-programmed-desorption of ammonia (NH3-TPD), Scanning Electron Microscope equipped with EDX detector (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) methods. The highest activity and methyl ester yields were obtained for the Pt/NZ catalyst. This catalyst showed the highest triglycerides conversion of 98.9% and fatty acids methyl esters yields of 94.6%. The activity results also confirmed the high activity of the carrier material (NZ) itself in the investigated reaction. Support material exhibited 90.5% of TG conversion and the Fatty Acid Methyl Esters yield (FAME) of 67.2%. Introduction of noble metals improves the TG conversion and FAME yield values. Increasing of the metal loading from 0.5 to 2 wt.% improves the reactivity properties of the investigated catalysts.

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X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

Powder Diffraction ◽

10.1017/s0885715620000767 ◽

2021 ◽

pp. 1-6

Author(s):

Mariana M. V. M. Souza ◽

Alex Maza ◽

Pablo V. Tuza

Keyword(s):

Crystal Structure ◽

Rietveld Method ◽

Pechini Method ◽

Powder Diffraction Data ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Modified Pechini Method ◽

Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

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ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

International Journal of Modern Physics B ◽

10.1142/s021797920201083x ◽

2002 ◽

Vol 16 (06n07) ◽

pp. 1047-1051

Author(s):

JIANPING MA ◽

ZHIMING CHEN ◽

GANG LU ◽

MINGBIN YU ◽

LIANMAO HANG ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Room Temperature ◽

Uv Light ◽

X Ray Diffraction ◽

X Ray ◽

Room Temperature Photoluminescence ◽

Composition And Structure ◽

Light Excitation ◽

Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

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Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

Materials Express ◽

10.1166/mex.2021.1963 ◽

2021 ◽

Vol 11 (5) ◽

pp. 724-731

Author(s):

Hemin Liu ◽

Qian Huang ◽

Liang Zhao

Keyword(s):

Ambient Temperature ◽

Sulfate Solution ◽

Sulfate Attack ◽

Limestone Powder ◽

X Ray Diffraction ◽

X Ray ◽

Mineral Phases ◽

Adverse Influence ◽

Powder Content ◽

Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

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Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.26-28.243 ◽

2007 ◽

Vol 26-28 ◽

pp. 243-246

Author(s):

Xing Hua Yang ◽

Jin Liang Huang ◽

Xiao Wang ◽

Chun Wei Cui

Keyword(s):

Crystal Structure ◽

Grain Size ◽

Electron Microscope ◽

Scanning Electron Microscope ◽

Sintering Temperature ◽

Solid Phase ◽

X Ray Diffraction ◽

X Ray ◽

Lanthanum Content ◽

Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

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

Journal of Materials Research ◽

10.1557/jmr.2000.0298 ◽

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.

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High-performance electrical properties of La-based perovskite ceramics for the functional phase of thick film resistors

10.21203/rs.3.rs-123794/v1 ◽

2020 ◽

Author(s):

Yongcheng Lu ◽

Yuanxun Li ◽

Daming Chen ◽

Rui Peng ◽

Qinghui Yang ◽

...

Keyword(s):

Crystal Structure ◽

Electrical Properties ◽

Thick Film ◽

High Performance ◽

Composite Ceramics ◽

X Ray Diffraction ◽

X Ray ◽

Alternative Material ◽

Perovskite Ceramics ◽

Scanning Electron

Abstract In order to explore an economical functional phase alternative material for thick film resistors, the crystal structure, microstructure, and electrical properties of (1-x)LSCN + xLCNZ (x = 0.0–1.0) composite ceramics were studied through solid-state reaction experiments. The composite ceramics were characterized by x–ray diffraction, scanning electron microscopy, energy dispersive x–ray spectroscopy, and DC four–probe method. Results suggested that the main phases of LSCN and LCNZ were formed, along with a small part of impurity phases. The addition of LCNZ to LSCN decreased the electrical conductivity and changed the TCR from positive to negative. Zero TCR could be achieved around 0.6 < x < 0.8 and relatively low absolute TCR values could be obtained for the samples of 0.4 ≤ x ≤ 0.8. The ceramic of 0.6LSCN + 0.4LCNZ showed the optimal performances of conductivity = 1923 S/cm, TCR = 379.54 ppm/℃, and relative density = 95.05%.

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Crystal Chemistry and High-Temperature Behaviour of Ammonium Phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the Burned Dumps of the Chelyabinsk Coal Basin

Minerals ◽

10.3390/min9080486 ◽

2019 ◽

Vol 9 (8) ◽

pp. 486 ◽

Cited By ~ 2

Author(s):

Andrey A. Zolotarev ◽

Elena S. Zhitova ◽

Maria G. Krzhizhanovskaya ◽

Mikhail A. Rassomakhin ◽

Vladimir V. Shilovskikh ◽

...

Keyword(s):

Crystal Structure ◽

High Temperature ◽

Unit Cell ◽

X Ray Diffraction ◽

Coal Basin ◽

Unit Cell Parameters ◽

Space Group ◽

X Ray ◽

Cell Parameters ◽

Mineral Phases

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.

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