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

Materials

Sang-Wook Chu¹  Chang-Sik Ha¹  Sung Soo Park¹  Liyi Shi²  Shuai Yuan² 

[1] Department of Polymer Science and Engineering, School of Chemical Engineering, Pusan National University, Busan 46241, Korea;Research Center of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, China;

关键词: crystalline SiO₂ structure;    mesoporous silica;    rearrangement of silica matrix;    alkali metal ions;    thermal treatment;   

DOI  :  10.3390/ma14185270

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown