Preparation of Chiral Mesoporous Silica Nanotubes and Nanoribbons Using a Dual-Templating Approach

Abstract

Single-handed helical silica nanotubes and nanoribbons have attracted much attention, due to their potential for applications in asymmetric catalysis and enantioseparation. However, their surface areas are usually lower than 200 m2/g. Herein, single-handed coiled silica nanoribbons with mesopores in their walls were prepared by changing the molar ratio of the chiral low-molecular-weight amphiphiles (LMWAs) and the F127 triblock copolymer, using a dual-templating approach. The obtained samples were characterized using field-emission scanning electron microscopy, transmission electron microscopy, N2 sorption measurements, and X-ray diffraction. The BET surface area reached 700 m2/g. The pore diameters did not change significantly at different LMWA/F127 triblock copolymer molar ratios. The formation of the coiled mesoporous silica nanoribbons was studied by taking TEM images at different times during the reaction. The results indicated that the morphology and the mesopores were controlled by the chiral LMWAs...