Effects of Co doping on Li[Ni0.5CoxMn1.5−x]O4 spinel materials for 5V lithium secondary batteries via Co-precipitation

2009 ◽  
Vol 189 (1) ◽  
pp. 752-756 ◽  
Author(s):  
Sung Woo Oh ◽  
Seung-Taek Myung ◽  
Han Byeol Kang ◽  
Yang-Kook Sun
Keyword(s):  
Lithium Secondary Batteries ◽  
Co Doping ◽  
Co Precipitation ◽  
Spinel Materials

Synthesis and characterization of YAG:Ce phosphors for white LEDs

2015 ◽  
Vol 23 (4) ◽  
Author(s):  
V. Tucureanu ◽  
A. Matei ◽  
A.M. Avram
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Blue Shift ◽  
Temperature Treatment ◽  
Yttrium Aluminium Garnet ◽  
White Leds ◽  
Light Emitting Devices ◽  
Co Doping ◽  
Co Precipitation ◽  
Average Size

AbstractWorldwide commercial interest in the production of cerium doped yttrium aluminium garnet (YAG:Ce) phosphors is reflected in the widespread use of white light emitting devices. Despite of the fact that YAG:Ce is considered a “cool phosphor” it is the most important in white LED technology. This article reviews the developed techniques for producing phosphors with superior photoluminescence efficiency, including solid-state reaction, sol-gel and (co)precipitation methods. Also, by co-doping with rare earth elements, a red/blue shift is reached in the spectrum. The characteristics of YAG:Ce phosphors are investigated because the properties of the phosphors are strongly influenced by the synthesis routes and the sintering temperature treatment. After the phase analysis, morphology and emission studies of the phosphors there may be seen the conditions when the transition from the amorphous phase to the crystalline phase appears, when luminescent properties are influenced by the crystalline form, purity, average size of the particles, co-doping and so on.

INFLUENCE OF Co DOPING ON STRUCTURAL, OPTICAL AND MAGNETIC STUDIES OF Co-DOPED CeO2 NANOPARTICLES

NANO ◽  
2010 ◽  
Vol 05 (06) ◽  
pp. 349-355 ◽  
Author(s):  
SHALENDRA KUMAR ◽  
B. H. KOO ◽  
S. K. SHARMA ◽  
M. KNOBEL ◽  
C. G. LEE
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Weak Ferromagnetism ◽  
Average Particle ◽  
Magnetic Studies ◽  
Co Doping ◽  
Diffraction Patterns ◽  
Co Precipitation ◽  
Co Doped

We have used the co-precipitation technique to synthesize nanocrystalline Co -doped CeO2 dilute magnetic semiconductors with Co concentrations ranging from 0.0–0.07. X-ray diffraction patterns (XRD) demonstrate that all the samples display single phase cubic structure without any impurity phase. Average particle sizes calculated from XRD and transmission electron microscopy (TEM) studies showed a gradual decrease with increase in Co ions concentration. UV–visible optical spectroscopy measurements reflect an energy band gap, which decreases with the increasing concentration of dopant (x ≤ 0.03). Raman spectra show an intensity loss of classical CeO2 vibration modes, which is an indication of considerable structural modifications and disorder in CeO2 lattice. Magnetic measurements revealed that all the samples exhibit a weak ferromagnetism at room temperature.

scholarly journals Hydrogen Production from Chemical Looping Steam Reforming of Ethanol over Perovskite-Type Oxygen Carriers with Bimetallic Co and Ni B-Site Substitution

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 372 ◽  
Author(s):  
Lin Li ◽  
Bo Jiang ◽  
Zhehao Sun ◽  
Qian Zhang ◽  
Duyu Li ◽  
...  
Keyword(s):  
Synergetic Effect ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Precipitation Method ◽  
Ethanol Conversion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Co Doping ◽  
Steam Reforming Of Ethanol ◽  
Co Precipitation

This paper describes the synthesis of a series of La1.4Sr0.6Ni1−xCoxO4 perovskite OCs using co-precipitation method by employing Co and Ni as the B-site components of perovskite and the synergetic effect of Co doping on chemical looping reforming of ethanol. A variety of techniques including N2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM) and H2 temperature-programmed reduction (TPR) were employed to investigate the physicochemical properties of the fresh and used OCs. The activity and stability in chemical looping reforming were studied in a fixed bed reactor at 600 °C and a S/C ratio of three. The synergetic effect between Ni and Co was able to enhance the catalytic activity and improve the stability of perovskite OCs. La1.4Sr0.6Ni0.6Co0.4O4 showed an average ethanol conversion of 92.4% and an average CO2/CO ratio of 5.4 in a 30-cycle stability test. Significantly, the H2 yield and purity reached 11 wt.% and 73%, respectively. The Co doping was able to significantly improve the self-regeneration capability due to the increase in the number of oxygen vacancies in the perovskite lattice, thereby enhancing the sintering resistance. Moreover, Co promotion also contributes to the improved WGS activity.

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