Pyris 1 tg analyzer

The morphology of the samples was examined using field-emission scanning electron microscopy (FE-SEM, ULTRA PLUS, ZEISS) and field-emission transmission electron microscopy (FE-TEM, JEOL, JEM-2100F). The phase analysis of the samples was carried out by X-ray diffraction (XRD, D8 Discover with GADDS, Bruker) using Cu K_α radiation (λ = 1.5418 Å). The chemical composition of the samples was investigated by X-ray photoelectron spectroscopy (XPS, Thermo Scientific K-Alpha) using a focused monochromatic Al K_α radiation at 12 kV and 20 mA. Raman spectroscopy (Jobin–Yvon LabRam, HR800, excitation source = 514 nm He–Ne laser) was conducted to confirm the presence of a graphitic structure in the samples. The surface areas of the samples were estimated using the Brunauer–Emmett–Teller (BET) method where N₂ was used as the adsorbate gas. Thermogravimetric analysis (TGA) was carried out using a Pyris 1 TG analyzer (Perkin Elmer) over the temperature range of 25–700 °C at a heating rate of 10 °C min⁻¹ under an air atmosphere.

The thermal stabilities of the ChNF samples were determined using a Pyris 1 TG analyzer (PerkinElmer, USA). A ChNF sample with a weight of ⁓ 10 mg was held at 110 °C for 20 min to remove moisture and then heated to 800 °C at a heating rate of 10 °C min⁻¹ under a N₂ flow rate of 50 mL min⁻¹.