THE OPTICAL AND EPR SPECTRA OF THE HYDROGEN ANNEALED KTiOPO4 CRYSTALS

1999 ◽  
Vol 13 (18) ◽  
pp. 645-648 ◽  
Author(s):  
V. A. NAZAROVA ◽  
V. N. EFIMOV ◽  
M. A. LARUHIN

In this work, the results of the hydrogen treatment and following that, the annealing in air of flux-grown KTiOPO 4 (KTP) crystals are represented. We have tried to correlate our optical and EPR results. The main conclusion is that the Ti 3+ A, B, C, D centers are not associated with optical absorption in the visible light region.

2016 ◽  
Vol 835 ◽  
pp. 359-365 ◽  
Author(s):  
Peerawas Kongsong ◽  
Lek Sikong ◽  
Sutham Niyomwas ◽  
Vishnu Rachpech

The degradation of fulvic acid (FA) using N–doped SnO2/TiO2 composite thin films coated on glass fibers prepared by sol–gel and dip–coating methods was investigated. The effects of nitrogen doping on coating morphology, physical properties, and FA degradation rates were experimentally determined. Nitrogen doping has an effect on shifting the optical absorption wavelength to visible light region, narrowing the band gap energy and reducing crystallite size which lead to the enhancement of photocatalytic performance. The optimal FA degradation rates of 40N/SnO2/TiO2 composite thin films under UV and solar irradiation are about 2.4 and 2.0 folds higher than that of TiO2 film, respectively due to its narrowest band gap energy (optical absorption wavelength shifting to visible light region) and small crystallite size influenced by nitrogen doped.


Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 457 ◽  
Author(s):  
Huoli Zhang ◽  
Changxin Zhu ◽  
Jianliang Cao ◽  
Qingjie Tang ◽  
Man Li ◽  
...  

In this study, α-Fe2O3@g-C3N4 photocatalyst was synthesized using an ultrasonic assisted self-assembly preparation method. The α-Fe2O3@g-C3N4 photocatalyst had a stronger optical absorption in the visible light region than pure graphitic carbon nitride (g-C3N4). The Z-Scheme heterojunction between α-Fe2O3 and g-C3N4 significantly inhibited the recombination of electrons and holes. The photocatalytic performances of α-Fe2O3@g-C3N4 photocatalyst were excellent in degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that 5 wt.% α-Fe2O3/g-C3N4 had the optimal photocatalytic activity because two-dimension (2D) α-Fe2O3 nanosheets can be well-dispersed on the surface of g-C3N4 layers by ultrasonic assisted treatment. A possible photocatalytic mechanism is also discussed.


2018 ◽  
Vol 20 (46) ◽  
pp. 29131-29141 ◽  
Author(s):  
Feifei Li ◽  
Changmin Shi ◽  
Dongchao Wang ◽  
Guangliang Cui ◽  
Pinhua Zhang ◽  
...  

The band gaps of type-II band structures in Mo–N stacking configuration are sensitive to the strains for MoS2/AlN hetero-structures, which exhibit more considerable optical absorption in the visible-light region than MoS2 and AlN monolayers.


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