Invia micro raman spectrometer

The crystal structures of the Fe₃O₄@C nanocomposite and pure C sample were studied by a powder X-ray diffractometer (XRD, RIGAKU, D/MAX 2550 VB/PC, Tokyo, Japan) at room temperature. X-ray photoelectron spectroscopy (XPS) was carried out on an ESCALab 250Xi spectrometer (Waltham, MA, USA) with an Al Kα source and the C 1s peak as the internal standard at 284.8 eV. The morphologies and texture of the samples were examined by field emission scanning electron microscopy (FE-SEM, Hitachi S-4800, Tokyo, Japan), and the element distribution was investigated with an energy-dispersive spectroscopy (EDS) detector (HITACHI, Tokyo, Japan). Raman spectra were conducted on an Invia Micro-Raman spectrometer (Renishaw, London, United Kingdom) with an excitation wavelength of 532 nm. Thermogravimetric measurements (TGA, NETZSCH TG209F1, Selb, Germany) were employed to determine the loading of carbon in Fe₃O₄@C in air.

UV-Vis spectra were taken with a Perkin Elmer Lambda 450 with an integration time of 0.5 s in an optical glass cuvette with a pathlength of 4 mm and screw-top lid with PTFE tape sealing the thread for air sensitive samples. When A > 1.0, the sample was diluted 10× and spectra values were multiplied by 10. SEM images and EDX spectra were taken using a Leo Gemini 1525 FEGSEM at an accelerating voltage of 10 keV for SEM, and 20 keV for EDX. TEM images were taken with a JEOL 2000 with an accelerating voltage of 100 keV. Raman spectra were taken with a ISA Jobin Yvon SPEX Raman exciting with a 25 mW 532 nm laser. Statistical Raman was performed with a Renishaw inVia micro-Raman Spectrometer with 633 nm laser. TGA measurements were taken with a Perkin Elmer Pyris 1 under N₂ at 60 mL min^–1 holding for 60 min at 100 °C before increasing the temperature at 10 °C min^–1 to 800 °C. AFM was performed on samples drop-cast onto cleaned (H₂SO₄/H₂O₂) silicon wafers, dried, and soaked in ethanol and water. AFM micrographs were taken by tapping mode on a Digital Instruments Multimode VIII AFM with Nanoscope IV Digital Instruments AFM controller (Veeco) using Nanosensor tapping mode probes (Windsor Scientific).