Direct Detailed Surface Structures 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, all these methods are short of conveying full surface information. In this work, low voltage scanning electron microscope (LVSEM) with beam deceleration technology was employed to image detailed surface pore structures of a ~2 nm pores diameters silica (MCM-41), SBA-15, KIT-6 and mesoporous silica nanospheres (MSNSs). The prospect for the development direction on ultra-high resolution Scanning Electron Microscopy (SEM) application was discussed in characterization of ordered porous materials. We demonstrate that complete dimension range of mesoscopic surface structure (2-50 nm) could be resolved by current low voltage SEM technology.