Model jsm7100f

Field emission scanning electron microscopy (FE-SEM, Model JSM-7100 F, JEOL, Tokyo, Japan) was used to evaluate the surface morphologies of all samples. Cs-corrected transmission electron microscopy (Cs correct TEM, Model JEM ARM 200F, JEOL, Tokyo, Japan) at an accelerating voltage of 80–200 kV was used to examine the lattice structures and exfoliation status of all samples. This unit included an EM unit, a high-angle annular dark-field detector, an FLC unit, an ultra-scan charge-coupled detector (CCD) camera unit, and an energy-dispersive spectrometry (EDS) unit. X-ray diffraction (XRD, D/Max Ultima III Rigaku Corporation, Tokyo, Japan) was used to determine the crystallinity of the material. UV-Vis absorption spectroscopy was used to monitor the catalytic decomposition of Cr(VI) (UV-3600 Plus UV-Vis-NIR Spectrophotometer, SHIMADZU, Kyoto, Japan). In addition, UV-Vis absorption techniques were used to assess photocatalytic stability and catalyst capacity. A laser with a 532 nm wavelength was linearly polarized from the confocal Raman spectroscopy measurements (NTEGRA Spectra, NT-MDT Co., Zelenograd, Russia). The objective lens used in all experiments had 0.7 NA and a magnification of 100× (Mitutoyo, Japan). A CCD (Andor, Abingdon-on-Thames, UK) cooled to 75 °C and a spectrometer with a grating of 1800 grooves/mm blazed at 500 nm were used to obtain Raman scattering signals.

The morphology and microstructure of the electrospun fibers were examined by scanning electron microscope (Model JSM- 7100F, Jeol Ltd., Tokyo, JPN). Samples were previously fixed 2.5% (v/v) glutaraldehyde in 0.1 M sodium cacodylate buffer pH 7.2, dehydrated in increasing concentrations of ethanol, dehydrated to a critical point with hexamethyldisilazane (Polysciences, Inc., Warrington, PA, USA) and coated with gold particles under vacuum in an ion sputtering device (JFC 1100, Jeol Ltd., Tokyo, JPN). The Image-J software (Java 8, NIH, Rockville Pike, MD, USA) was used to analyze the captured images. The average diameter of the fibers and pore size were calculated after measuring at least 100 fibers, and the data obtained were subjected to statistical analysis using the GraphPad Prism software version 8 (GraphPad Software, San Diego, CA, USA).