Effect of Alkali-Earth Metal Fluorides on Phase and Luminescence of Magnesium Germanate Phosphors

2010 ◽  
Vol 157 (11) ◽  
pp. J397 ◽  
Author(s):  
Tae-Gon Kim ◽  
Taehyung Kim ◽  
Young-Sic Kim ◽  
Seoung-Jae Im
Keyword(s):  
Earth Metal ◽  
Alkali Earth Metal ◽  
Alkali Earth ◽  
Metal Fluorides ◽  
Magnesium Germanate

scholarly journals SBA-15 with Crystalline Walls Produced via Thermal Treatment with the Alkali and Alkali Earth Metal Ions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5270
Author(s):  
Sung Soo Park ◽  
Sang-Wook Chu ◽  
Liyi Shi ◽  
Shuai Yuan ◽  
Chang-Sik Ha
Keyword(s):  
Metal Ions ◽  
Pore Size ◽  
Metal Ion ◽  
Pore Diameter ◽  
Earth Metal ◽  
Silica Matrix ◽  
Alkali Earth Metal ◽  
Alkali Earth ◽  
Large Pore ◽  
Large Pore Size

Crystalline walled SBA-15 with large pore size were prepared using alkali and alkali earth metal ions (Na+, Li+, K+ and Ca2+). For this work, the ratios of alkali metal ions (Si/metal ion) ranged from 2.1 to 80, while the temperatures tested ranged from 500 to 700 °C. The SBA-15 prepared with Si/Na+ ratios ranging from 2.1 to 40 at 700 °C exhibited both cristobalite and quartz SiO2 structures in pore walls. When the Na+ amount increased (i.e., Si/Na increased from 80 to 40), the pore size was increased remarkably but the surface area and pore volume of the metal ion-based SBA-15 were decreased. When the SBA-15 prepared with Li+, K+ and Ca2+ ions (Si/metal ion = 40) was thermally treated at 700 °C, the crystalline SiO2 of quartz structure with large pore diameter (i.e., 802.5 Å) was observed for Ca+2 ion-based SBA-15, while no crystalline SiO2 structures were observed in pore walls for both the K+ and Li+ ions treated SBA-15. The crystalline SiO2 structures may be formed by the rearrangement of silica matrix when alkali or alkali earth metal ions are inserted into silica matrix at elevated temperature.

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