Synthesis of SBA-15 assembled with silicon nanoparticles with different morphologies for oxygen sensing

In this paper, our effort is focused on preparation and oxygen sensing of fluorescent silicon nanoparticles (Si NPs) assembled in three kinds of mesoporous SBA-15 with different morphologies, including spherical mesoporous SBA-15 (SPSBA-15), long rod-like mesoporous SBA-15 (LRSBA-15) and hexagonal prism-like mesoporous SBA-15 (HPSBA-15). The relationship of structure and sensing properties in mesoporous materials is studied. Small angle powder X-ray diffraction (SAXRD), Fourier transform infrared spectrometer (FT-IR), Brunauer-Emmett-Teller (BET), Discrete-Fourier-Transform (DFT) analyses and X-ray photoelectron spectroscopy (XPS) are used to characterize their structural properties. The obtained mesoporous SPSBA-15, LRSBA-15 and HPSBA-15 possess abundant Si-O-Si bands of the inorganic framework and high surface-volume ratios. Particularly, mesoporous HPSBA-15 materials exhibit the largest surface areas than other two mesoporous materials. Accordingly, the adding volume of Si NPs was 8 ml in mesoporous HPSBA-15. At the same time, the hybrid materials show the shortest response time of 2.2 s and recovery time of 11.2 s. This result can be attributed to the uniform and nearly parallel porous structure of the HPSBA-15 materials supporting with large surface areas and narrow pore size distributions. Therefore, the properties in oxygen sensing can be improved by using mesoporous SBA-15 materials with larger BET surface area.