Deactivation of Alumina Supported Catalysts Due to Spinel Formation

1994 ◽  
Vol 344 ◽  
Author(s):  
P. H. Bolt ◽  
M. E. Van Ipenburg ◽  
J. W. Geus ◽  
F. H. P. M. Habraken
Keyword(s):  
Transition Metal ◽  
Reaction Rate ◽  
Rutherford Backscattering Spectrometry ◽  
Supported Catalysts ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spinel Formation ◽  
Transition Metal Element ◽  
Metal Element

AbstractAn important cause of deactivation of alumina supported transition metal (oxide) catalysts is a solid state reaction between the active component and the support. We therefore studied the hightemperature behavior of Me layers (Me = Co, Ni, Cu and Fe) on polycrystalline α-A12O3 and γ- Al2O3 substrates. The samples were first oxidized at moderate temperatures and then annealed at high temperatures (up to 1000 °C) in O2, N2, or N2/O2 mixtures. The interfacial reaction to MeA12O4 was assessed using Rutherford Backscattering Spectrometry and X-ray diffraction. The reaction rate strongly depends on the transition metal element Me: Fe < Ni < Co < Cu. Low oxygen pressures favour spinel formation. γ-A12O3 shows a much higher reactivity towards the MeOx overlayers than α-Al2O3.

Electrochemical Behavior of LiCo(1-x)MnxO2 Crystalline Powders

2014 ◽  
Vol 895 ◽  
pp. 334-337
Author(s):  
Azira Azahidi ◽  
Norlida Kamarulzaman ◽  
Kelimah Elong ◽  
Nurhanna Badar ◽  
Nurul Atikah Mohd Mokhtar
Keyword(s):  
Partial Substitution ◽  
Li Ion Batteries ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
X Ray ◽  
Capacity Loss ◽  
Transition Metal Element ◽  
Metal Element ◽  
Li Ion ◽  
Mn Doped

LiCoO2 is a well-known cathode material used in commercial Li-ion batteries but it has its own limitations in terms of cost and toxicity. Improvement of the material by partial substitution of Co with other transition metals is one of the alternative and effective ways to overcome the limitations and improve the electrochemical performance of cathode materials. The transition metal element used for the substitution has to be cheaper and non-toxic thus Mn is chosen here. LiCo(1-x)MnxO2 (x= 0.1, 0.2, 0.3) we synthesized by a novel route using a self-propagating combustion (SPC) method. The samples are analyzed using X-Ray Diffraction (XRD) for phase purity and Field Emission Scanning Electron Microscopy (FESEM) for morphology and particle size studies. The materials obtained are phase pure. In terms of electrochemical activity, though it does not show better first cycle discharge capacity, the Mn doped materials have improved capacity retention. Results showed that LiCo0.9Mn0.1O2 and LiCo0.8Mn0.2O2 exhibited less than 8 % capacity loss in the 20th cycle compared to 12 % for LiCoO2.

Silicide Formation By High Dose Transition Metal Implants Into Si.

1985 ◽  
Vol 51 ◽  
Author(s):  
F. H. Sanchez ◽  
F. Namavar ◽  
J. I. Budnick ◽  
A. Fasihudin ◽  
H. C. Hayden
Keyword(s):  
Transition Metal ◽  
Rutherford Backscattering Spectrometry ◽  
Atomic Diffusion ◽  
High Dose ◽  
Silicide Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Implants ◽  
Metal Silicides ◽  
Suitable Technique

ABSTRACTWe report preliminary results of a study on silicide formation by means of high dose transition metal implants into Si (100) single crystals.100 keV Cr+, Fe+, Co+ and Ni+ were implanted at room temperature. For the Cr+, Fe+ and Ni+ implants, no silicide formation was observed after implantation. However, both Rutherford Backscattering Spectrometry (RBS) and X-Ray Diffraction (XRD) results clearly indicated the existence of CrSi2 after the Cr-Si samples were annealed 4 hours at 550°C. In the case of the Fe+ and Ni+ implants, FeSi2 and NiSi2 were identified by XRD after annealing the implanted samples half an hour at 400°C. A layer of CoSi of about 1000 Å was observed in the as implanted Co-Si samples by both RBS and XRD.Ni+ ions accelerated to 150 keV were implanted at 350°C. A much broader distribution and higher retention of Ni was obtained in this case, showing evidence of long range atomic diffusion. NiSi and polycrystalline silicon were observed by XRD in the as implanted samples.The possibility of high dose ion implantation as a suitable technique for producing transition metal silicides is discussed.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

scholarly journals MOVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics

2000 ◽  
Vol 5 (S1) ◽  
pp. 412-424
Author(s):  
Jung Han ◽  
Jeffrey J. Figiel ◽  
Gary A. Petersen ◽  
Samuel M. Myers ◽  
Mary H. Crawford ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Optoelectronic Devices ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Energy ◽  
Movpe Growth ◽  
Pl Emission

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

Effect of transition metal element substitution on magnetoelectric properties of BiFeO3-BaTiO3 ceramics

2021 ◽  
Vol 859 ◽  
pp. 158224
Author(s):  
Miao Miao Niu ◽  
Juan Liu ◽  
Tu Lai Sun ◽  
Run Zu Jiang ◽  
Dian Hui Hou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Element Substitution ◽  
Magnetoelectric Properties ◽  
Transition Metal Element ◽  
Metal Element

Yttrium Implantation and Manganese Addition Element Effects on the High Temperature Oxidation Resistance of a Model Steel

2008 ◽  
Vol 595-598 ◽  
pp. 897-905
Author(s):  
Eric Caudron ◽  
Régis Cueff ◽  
Christophe Issartel ◽  
N. Karimi ◽  
Frédéric Riffard ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
High Temperatures ◽  
Mixed Oxides ◽  
Rutherford Backscattering Spectrometry ◽  
High Energy ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
Steel Oxidation ◽  
Yttrium Implantation

Manganese addition and subsequent yttrium implantation effects on extra low carbon steel were studied by Rutherford Backscattering Spectrometry (RBS), Reflection High Energy Electron Diffraction (RHEED), X-ray Diffraction (XRD) and Glancing Angle X-ray Diffraction (GAXRD). Thermogravimetry and in situ X-Ray Diffraction at 700°C and PO2=0.04 Pa for 24h were used to determine the manganese alloying addition and subsequent yttrium implantation effects on reference steel oxidation resistance at high temperatures. This study clearly shows the combined effect of manganese alloying addition and subsequent yttrium implantation which promotes the formation of several yttrium mixed oxides seem to be responsible for the improved reference steel oxidation resistance at high temperatures.

Purification, Crystallization and Preliminary X-Ray Diffraction Studies on Goat (Capra hircus) Hemoglobin - A Low Oxygen Affinity Species

2009 ◽  
Vol 16 (4) ◽  
pp. 454-456 ◽  
Author(s):  
Ponnuraj Moorthy ◽  
Kamariah Neelagandan ◽  
Moovarkumudalvan Balasubramanian ◽  
Mondikalipudur Ponnuswamy
Keyword(s):  
Oxygen Affinity ◽  
Capra Hircus ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hemoglobin A ◽  
Low Oxygen Affinity

Transition-Metal Element (Ni, Co)-Doped MgO Microflowers for Electrochemical Biosensor Applications

JOM ◽  
2018 ◽  
Vol 71 (1) ◽  
pp. 279-284 ◽  
Author(s):  
A. Anusiya ◽  
B. Jansi Rani ◽  
G. Ravi ◽  
R. Yuvakkumar ◽  
S. Ravichandran ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electrochemical Biosensor ◽  
Transition Metal Element ◽  
Metal Element ◽  
Biosensor Applications ◽  
Co Doped

Long-term Room Temperature Instability in Thermal Conductivity of InGaZnO Thin Films

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1631-1636 ◽  
Author(s):  
Boya Cui ◽  
D. Bruce Buchholz ◽  
Li Zeng ◽  
Michael Bedzyk ◽  
Robert P. H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Storage Time ◽  
Laser Deposition ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
3Ω Method ◽  
X Ray

ABSTRACTThe cross-plane thermal conductivities of InGaZnO (IGZO) thin films in different morphologies were measured on three occasions within 19 months, using the 3ω method at room temperature 300 K. Amorphous (a-), semi-crystalline (semi-c-) and crystalline (c-) IGZO films were grown by pulsed laser deposition (PLD), followed by X-ray diffraction (XRD) for evaluation of film quality and crystallinity. Semi-c-IGZO shows the highest thermal conductivity, even higher than the most ordered crystal-like phase. After being stored in dry low-oxygen environment for months, a drastic decrease of semi-c-IGZO thermal conductivity was observed, while the thermal conductivity slightly reduced in c-IGZO and remained unchanged in a-IGZO. This change in thermal conductivity with storage time can be attributed to film structural relaxation and vacancy diffusion to grain boundaries.

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