scholarly journals Structural and UV-Vis Diffuse Reflection Spectroscopy Studies of Nanosized Sr0.5Ba0.5Nb2O6 synthesized by Co-Precipitation method

Author(s):  
Sanjay B. Nagdeote

The Sr0.5Ba0.5Nb2O6 (SBN-50) is Synthesis by coprecipitation method in nanoscale. TG/DTA shows the reaction and tetragonal phase formation occur at low temperatures, due to which the good homogeneity and morphology of the particles is observed. The average size of the particles was found to be ~ 45 nm. The lattice parameters is found very close to the reported values of single crystals despite method of synthesis and size of the particles. A reflectance spectrum in UV and visible regions shows less reflectance for 337nm and 519nm respectively.

2015 ◽  
Vol 87 (17) ◽  
pp. 8740-8747 ◽  
Author(s):  
Stephanie A. DeJong ◽  
Zhenyu Lu ◽  
Brianna M. Cassidy ◽  
Wayne L. O’Brien ◽  
Stephen L. Morgan ◽  
...  

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 123 ◽  
Author(s):  
Andrea Bellmann ◽  
Christine Rautenberg ◽  
Ursula Bentrup ◽  
Angelika Brückner

UV–Vis spectroscopy as well as in situ FTIR spectroscopy of pyridine and CO adsorption were applied to determine the nature of Co species in microporous, mesoporous, and mixed oxide materials like Co–ZSM-5, Co/Na–ZSM-5, Co/Al–SBA-15, and Co/Al2O3–SiO2. Because all sample types show comparable UV–Vis spectra with a characteristic band triplet, the former described UV–Vis band deconvolution method for determination and quantification of individual cationic sites in the zeolite appears doubtful. This is also confirmed by results of pyridine and CO adsorption revealing that all Co–zeolite samples contain two types of Co2+ species located at exchange positions as well as in oxide-like clusters independent of the Co content, while in Co/Al–SBA-15 and Co/Al2O3–SiO2 only Co2+ species in oxide-like clusters occur. Consequently, the measured UV–Vis spectra represent not exclusively isolated Co2+ species, and the characteristic triplet band is not only related to γ-, β-, and α-type Co2+ sites in the zeolite but also to those dispersed on the surface of different oxide supports. The study demonstrates that for proper characterization of the formed Co species, the use of complementary methods is required.


2006 ◽  
Vol 14 (1) ◽  
pp. 415 ◽  
Author(s):  
Hai-Bo Liu ◽  
Yunqing Chen ◽  
Glenn J. Bastiaans ◽  
X.-C. Zhang

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