Monodispersed silica spheres with solid core and fibrous shell were successfully synthesized using a biphase reaction. Both the thickness and the pore size of the fibrous shell could be finely tuned by changing the stirring rate during synthesis. When stirring was adjusted from 0 to 800 rpm, the thickness of the shell could be tuned from 13 to 67 nm and the pore size from 5 to 16 nm. By continuously adjusting the stirring rate, fibrous shells with hierarchical pore structure ranged from 10 to 28 nm and thickness up to 200 nm could be obtained in one pot. We demonstrate that fibrous shells with controllable thickness and pore size could be coated on silica cores with diameters from 0.5 to 3 μm while maintaining the monodispersity of the particles. As a result of the unique fibrous structure, the BET surface area could reach ∼233 m2 g–1 even though the shell thickness was less than 150 nm. The core–shell particles were modified with C18, packed, and then used in high-performance liquid chromatography (HPLC) separation, showing separation performance as high as 2.25 × 105 plates m–1 for naphthalene and back pressure as low as 5.8 MPa. These silica microspheres with fibrous shells are expected to have great potential for practical applications in HPLC.
Lanfei Wei,Jiaquan Liu,Qiuman Zhou,Shaolong Liu,Zhifeng Su,Yurong Yan
Bismuth trioxide (Bi 2 O 3 ) acts as an ideal material for supercapacitors because of its high theoretical specific capacity, but its crystal form and compact accumulation limit its specific capacitance below its theoretical value of 1370 F g -1 . In this study, a specific kapok fiber@chitosan-derived carbon (KCC) doping inside β/α hybrid-crystal Bi 2 O 3 (KCC-Bi 2 O 3 ) was constructed by KCC assisting to enhance the contact area between Bi-MOF and air during calcination. A specific capacitance of 1135 F g -1 at 1 A g -1 was obtained for KCC-Bi 2 O 3 , which matched 82.3 % of its theoretical value. An asymmetric capacitor, with KCC-Bi 2 O 3 as a negative electrode and NiCo-LDH as a positive electrode, exhibits a potential window of 1.6 V and an energy density of 17.3 Wh kg -1 at 800 W kg -1 . The result demonstrates that incorporating a KCC carbon source can significantly enhance the capacitance of mixed crystal form Bi 2 O 3 , highlighting its potential in supercapacitor applications.
危险品化学品经营许可证（带存储）