Direct Detailed Surface Structure Imaging of Mesoporous Silica by Low-Voltage Scanning Electron Microscopy

Mesoporous silica and its derivatives might enable applications ranging from biomedicine to petrochemical processing. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2 adsorption–desorption measurements are usually used to characterize the ordered porous system. However, none of these methods convey the full surface information. In this work, a low-voltage scanning electron microscope (LVSEM) with beam deceleration technology was employed to image detailed surface structures of ~2 nm pore size silica (MCM-41), SBA-15, KIT-6, and mesoporous silica nanospheres (MSNSs). The prospects for the development of this application of ultra-high-resolution scanning electron microscopy (SEM) are discussed in the characterization of the ordered porous materials. We demonstrate that the complete dimension range of the mesoscopic surface structure (2–50 nm) could be resolved by current low-voltage SEM technology.