Synthesis of Cerium Phosphate White Pigments from Cerium Oxalate

Catalytically active cerium dioxide is used as light reflection materials for cosmetic applications. Therefore, cosmetics containing this pigment too much cause oxidation of the skin. Therefore, the substitute for cerium dioxide is required to prepare the cosmetics without catalytic activity. Herein, as novel white pigments for use in cosmetics, cerium phosphates were prepared from cerium oxalate under various conditions. The chemical composition, powder properties, catalytic activity, color phase, and smoothness of the cerium phosphates were evaluated. All samples had weak unknown peaks in XRD patterns. Samples prepared at high temperature and for long time indicated the peaks of phosphate in IR spectra. Samples prepared in this work had no photo and oxidation catalytic activities. Samples prepared at high temperature and for long time indicated enough high whiteness and high smoothness.

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From Ru nanoparticle-encapsulated metal–organic frameworks to highly catalytically active Cu/Ru nanoparticle-embedded porous carbon

Journal of Materials Chemistry A ◽

10.1039/c6ta10748f ◽

2017 ◽

Vol 5 (10) ◽

pp. 4835-4841 ◽

Cited By ~ 54

Author(s):

Pradip Pachfule ◽

Xinchun Yang ◽

Qi-Long Zhu ◽

Nobuko Tsumori ◽

Takeyuki Uchida ◽

...

Keyword(s):

Catalytic Activity ◽

High Temperature ◽

Porous Carbon ◽

Metal Organic Frameworks ◽

Ammonia Borane ◽

Carbon Composites ◽

High Catalytic Activity ◽

Catalytically Active ◽

Metal Organic

High-temperature pyrolysis of Ru nanoparticle-encapsulated MOF (Ru@HKUST-1) afforded ultrafine Cu/Ru nanoparticle-embedded porous carbon composites (Cu/Ru@C), which show high catalytic activity for ammonia borane hydrolysis.

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Influence of preparation conditions on physicochemical properties and catalytic activity of stabilized zeolites

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19802042 ◽

1980 ◽

Vol 45 (7) ◽

pp. 2042-2048

Author(s):

Jana Nováková ◽

Ludmila Kubelková ◽

Blanka Wichterlová

Keyword(s):

Catalytic Activity ◽

High Temperature ◽

Structural Changes ◽

Oh Groups ◽

Stabilization Process ◽

Preparation Conditions ◽

Catalytically Active ◽

Active Electron ◽

Acid Centers ◽

Stabilization Temperature

Highly decationized zeolite NH4NaY, stabilized by water vapour under steaming conditions at 1030 K, was characterized by its lattice constant, sorption capacity, quantity of extralattice Al, number and character of OH groups present after dehydration in vacuum at 670 K. The catalytic activity and the effect of Lewis and Broensted type acid centers were tested by oligomeration of ethylene and propylene at 310 K and isotopic exchanges of ethylene-d4 + OH and propylene-d6 + OH at 570 K. The properties of this zeolite were compared with zeolites stabilized under selfsteaming conditions at 1040 and 820 K. Structural changes caused by the stabilization process are more pronounced with the steamed zeolite than with the selfsteamed one; in the latter case they diminish with stabilization temperature. Accordingly, the results of catalytic measurements reveal the effect of strong Broensted acid centers in the case of low-temperature selfsteamed zeolite; these centers apparently originate from remainders of the original decationized zeolite. The high-temperature self-steamed zeolite is essentially inactive, whereas the activity of the high-temperature steamed zeolite suggest the presence of catalytically active electron-acceptor centers.

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Microstructural characterization of plasma-processed Ti-Al metal matrix composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154731 ◽

1989 ◽

Vol 47 ◽

pp. 552-553

Author(s):

M. G. Burke ◽

M. N. Gungor ◽

M. A. Burke

Keyword(s):

High Temperature ◽

Titanium Aluminide ◽

Plasma Processing ◽

Microstructural Characterization ◽

High Temperature Strength ◽

Matrix Composites ◽

Intermetallic Matrix ◽

Long Time ◽

Strength And Stiffness ◽

Intermetallic Matrix Composites

Intermetallic matrix composites are candidates for ultrahigh temperature service when light weight and high temperature strength and stiffness are required. Recent efforts to produce intermetallic matrix composites have focused on the titanium aluminide (TiAl) system with various ceramic reinforcements. In order to optimize the composition and processing of these composites it is necessary to evaluate the range of structures that can be produced in these materials and to identify the characteristics of the optimum structures. Normally, TiAl materials are difficult to process and, thus, examination of a suitable range of structures would not be feasible. However, plasma processing offers a novel method for producing composites from difficult to process component materials. By melting one or more of the component materials in a plasma and controlling deposition onto a cooled substrate, a range of structures can be produced and the method is highly suited to examining experimental composite systems. Moreover, because plasma processing involves rapid melting and very rapid cooling can be induced in the deposited composite, it is expected that processing method can avoid some of the problems, such as interfacial degradation, that are associated with the relatively long time, high temperature exposures that are induced by conventional processing methods.

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UNS N06455

Alloy Digest ◽

10.31399/asm.ad.ni0367 ◽

1989 ◽

Vol 38 (1) ◽

Keyword(s):

Corrosion Resistance ◽

High Temperature ◽

Stress Corrosion Cracking ◽

Temperature Stability ◽

Heat Treating ◽

High Ductility ◽

High Temperature Stability ◽

Nickel Chromium ◽

Long Time ◽

Resistance To Stress

Abstract UNS NO6455 is a nickel-chromium-molybdenum alloy with outstanding high-temperature stability as shown by high ductility and corrosion resistance even after long-time aging in the range 1200-1900 F. The alloy also has excellent resistance to stress-corrosion cracking and to oxidizing atmospheres up to 1900 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-367. Producer or source: Nickel and nickel alloy producers.

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UNS R54620

Alloy Digest ◽

10.31399/asm.ad.ti0086 ◽

1987 ◽

Vol 36 (7) ◽

Keyword(s):

Titanium Alloy ◽

High Temperature ◽

Time Use ◽

Temperature Stability ◽

High Strength ◽

Heat Treating ◽

High Temperature Stability ◽

Beta Titanium Alloy ◽

Beta Titanium ◽

Long Time

Abstract UNS No. R54620 is an alpha-beta titanium alloy. It has an excellent combination of tensile strength, creep strength, toughness and high-temperature stability that makes it suitable for service to 1050 F. It is recommended for use where high strength is required. It has outstanding advantages for long-time use at temperatures to 800 F. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-86. Producer or source: Titanium alloy mills.

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Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19881636 ◽

1988 ◽

Vol 53 (8) ◽

pp. 1636-1646 ◽

Cited By ~ 8

Author(s):

Viliam Múčka ◽

Kamil Lang

Keyword(s):

Hydrogen Peroxide ◽

Catalytic Activity ◽

Extreme Values ◽

Catalytic Properties ◽

Active Components ◽

Catalytic Systems ◽

Heterogeneous Catalytic ◽

Peroxide Decomposition ◽

Two Component ◽

Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

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Role of CO2 During Oxidative Dehydrogenation of Propane Over Bulk and Activated-Carbon Supported Cerium and Vanadium Based Catalysts

Catalysis Letters ◽

10.1007/s10562-020-03519-y ◽

2021 ◽

Author(s):

Petar Djinović ◽

Janez Zavašnik ◽

Janvit Teržan ◽

Ivan Jerman

Keyword(s):

Catalytic Activity ◽

Activated Carbon ◽

Oxidative Dehydrogenation ◽

Active Phase ◽

Lattice Oxygen ◽

Chemisorbed Oxygen ◽

Catalytically Active ◽

Temperature Programmed ◽

Propane Cracking

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract

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Photoluminescence Properties of Ca3Si2O7: Pr3+ Orange-Red Phosphors Prepared by High-Temperature Solid-State Method

Zeitschrift für Naturforschung A ◽

10.1515/zna-2018-0050 ◽

2018 ◽

Vol 73 (6) ◽

pp. 555-558 ◽

Cited By ~ 3

Author(s):

Zhi-Qing Peng ◽

Rong Chen ◽

Wen-Lin Feng

Keyword(s):

Crystal Structure ◽

High Temperature ◽

Solid State ◽

Solid State Method ◽

Light Emitting ◽

Light Emitting Devices ◽

Red Phosphors ◽

Typical Sample ◽

State Method ◽

Xrd Patterns

AbstractNovel luminescent materials Ca3-xSi2O7: xPr3+ were successfully prepared by the high-temperature solid-state method. The crystal structure, morphology, and optical spectrum were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopy, respectively. The XRD patterns of the samples indicate that the crystal structure is monoclinic symmetry. The SEM shows that the selected sample has good crystallinity although its appearance is irregular and scalelike. The peak of the excitation spectrum of the sample is located at around 449 nm, corresponding to 3H4→3P2 transition of Pr3+. The peak of the emission spectrum of the sample is situated at around 612 nm which is attributed to 3P0→3H6 transition of Pr3+, and the colour is orange-red. The optimum concentration for Pr3+ replaced Ca2+ sites in Ca3Si2O7: Pr3+ is 0.75 mol%. The lifetime (8.48 μs) of a typical sample (Ca2.9925Pr0.0075)Si2O7 is obtained. It reveals that orange-red phosphors Ca3-xSi2O7: xPr3+ possess remarkable optical properties and can be used in white light emitting devices.

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Catalytic activity of Co-åkermanite and Co-pyroxene in oxidation reactions

Canadian Journal of Chemistry ◽

10.1139/v11-061 ◽

2011 ◽

Vol 89 (8) ◽

pp. 939-947 ◽

Cited By ~ 5

Author(s):

Irena Mihailova ◽

Dimitar Mehandjiev

Keyword(s):

Catalytic Activity ◽

Solid Phase ◽

Sol Gel ◽

Cobalt Content ◽

Octahedral Coordination ◽

Tetrahedral Coordination ◽

Oxidation Reactions ◽

Oxidation Of Co ◽

Phase Synthesis ◽

Catalytically Active

Two calcium–cobalt silicates were synthesized in which cobalt occupies different structural positions. The crystal phases belong to two main structural silicate types. In the Co-åkermanite structure (Ca2CoSi2O7), cobalt cations take tetrahedral coordination toward oxygen atoms. In the Co-pyroxene structure of CaCoSi2O6, cobalt displays octahedral coordination. Ca2CoSi2O7 was prepared by solid-phase synthesis and CaCoSi2O6 was prepared by sol–gel method. The synthesis of the phases was confirmed by XRD, FTIR, and EPR data. On the basis of the XPS analysis, it can be concluded that Co2+ cations exist in the studied silicates. Thus, it is possible to study the catalytic activity of two silicate phases containing Co2+ cations in different coordinations: tetrahedral and octahedral. It was found that cobalt silicates with crystal structures corresponding to pyroxene and åkermanite possess catalytic activity in the reactions of complete oxidation of CO and toluene. Co-pyroxene exhibits higher catalytic activity than Co-åkermanite, but the higher cobalt content on the surface of Co-pyroxene should also be taken into account. Then, it turns out that catalytically active complexes with Со2+ ions in tetrahedral coordination are more efficient than those with such ions in octahedral coordination when equal concentrations of cobalt were used on the surface of the catalysts.

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