Nanosem 430 field emission scanning electron microscope

The structures of the samples were investigated by X-ray diffraction (XRD) performed on a Rigaku D/Max-2500 diffractometer with Cu Kα radiation. Raman spectrum was performed with a Renishaw InVia Raman spectrometer using laser excitation at 514.5 nm. Lorentzian fitting was carried out to confirm the positions and widths of the D and G bands. I_D and I_G are the intensities of the D and G bands, respectively. X-ray photoelectron spectroscopy (XPS) analysis was performed using AXIS HIS 165 spectrometer (Kratos Analytical) with a monochromatized Al Kα X-ray source (1486.7 eV). Scanning electron microscopy (SEM) images were obtained on an FEI NanoSem 430 field emission scanning electron microscope using an accelerating voltage of 20 kV. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM) were conducted in an FEI Tecnai G2 F20 electron microscope using an acceleration voltage of 200 kV.

A series of instruments were used to characterize SiO₂–CHO–APBA and its intermediates. Fourier-transform infrared spectra were analyzed with a TENSOR 27 FT-IR Spectroscopy (Bruker, Germany) by the KBr method. The morphology of SiO₂–CHO–APBA was characterized by Nanosem 430 Field emission scanning electron microscope (FEI, USA) and JEM100CXII transmission electron microscope (JEOL, Japan). Its specific surface was measured using a Brunauer–Emmett–Teller surface area analyzer with NAVO Station (Quantachrome, USA) based on the nitrogen adsorption and desorption method. The content of B element in SiO₂–CHO–APBA was determined by inductively coupled plasma mass spectrometer (Agilent 5110, USA). Thermal analysis of SiO₂–CHO–APBA was carried out with a TGA 550 analyzer (Discovery, USA) under N₂ flow at a heating rate of 10 °C min⁻¹ in the range of 30–600 °C. The concentration of Cr(vi) and Cr(iii) in the supernatant was measured by Cary 60 UV-Vis spectrophotometer (Agilent, USA).