Nanonova 230

Fourier transform infrared (FT-IR) spectra were obtained on a Spectrum 100 (Perkin-Elmer, USA) with a KBr pellet. Magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were measured at room temperature on an Agilent VNMRS 600 spectrometer. The thermogravimetric analysis (TGA) was carried out using a STA 8000 thermal analyzer at a heating rate of 10 °C min⁻¹ under air and nitrogen atmosphere. Powder X-ray diffraction (PXRD) patterns were recorded using a High-Power X-Ray Diffractometer D/MAX 2500 V/PC (Cu-Kα radiation, 40 kV, 200 mA, λ = 1.54056 Å) (Rigaku Inc., Japan). Scanning electron microscope (SEM) measurements with Pt coated samples were obtained by a Field Emission Scanning Electron Microscope Nanonova 230 (FEI Inc., USA). X-ray photoelectron spectroscopy (XPS) was performed on an X-ray Photoelectron Spectrometer K-alpha (Thermo Fisher, UK). Elemental analysis (EA) data was obtained from a Flash 2000 Analyzer (Thermo Scientific Inc., USA). High-resolution transmission electron microscopy (HR-TEM) was conducted using a JEM-2100F microscope (JEOL inc., Japan) at an operating voltage of 200 keV. The samples were prepared by drop casting dispersed ethanol on a holey carbon TEM grid, and drying in an oven at 50 °C under vacuum.

The morphology of the surface and the transversal section of the samples were observed using the Scanning Electron Microscope (SEM) (Nano Nova 230, FEI, Hillsboro, OR, USA). The lyophilized films were cut into two fragments of 2 cm diameter to place them in the aluminum supports adapted to the machine. A gold coating was applied to increase their conductivity through the sample. The applied accelerating voltage was set on 15.0 kV, with an increase of 500 and 2000× [31 (link)]. The experiment was carried out in triplicate.

The morphologies of the samples were characterized on a field emission scanning electron microscope (SEM, Nanonova 230, FEI, USA) and high-resolution transmission electron microscopy (HR-TEM, JEM-2100F, JEOL, Japan). XRD patterns were obtained from a high-power X-ray diffractometer (D/MAZX 2500V/PC, Rigaku, Japan). The XPS test was conducted using an X-ray photoelectron spectrometer (K-alpha, Thermo Fisher Scientific, UK). The XAFS test was performed at the 6D UNIST-PAL beam-line of Pohang Light Source (PLS-II) in Korea. The specific surface area was analyzed using nitrogen adsorption–desorption isotherms, and the Brunauer-Emmett-Teller (BET) method (BELSORP-max, BEL, Japan). The TGA was conducted on a Thermogravimetric Analyzer (Q200, TA, USA).