Invia micro raman spectroscopy system

Crystal structure information of sample was conducted by D8 Discover X-ray diffractometer (XRD) using Cu-Kα X-ray source with radiation. Field emission scanning electron microscopy (FESEM, JEOL-7100F) and Energy-Dispersive Spectroscopy (EDS) were used to analyze morphology and element distribution. Transmission electron microscopy (TEM) images were obtained by using JEM-2100F with acceleration voltage 200 kV. Fourier transform infrared Spectroscopy (FTIR) measurements were collected by using Nicolet 6700 (Thermo Fisher Scientific Co., USA) IR spectrometer with wavenumber range from 400 to 4000 cm⁻¹. Thermogravimetric analysis (TGA) was conducted with a STA-449C from 30 to 600 °C. The Tristar II 3020 instrument was performed to measure BET specific surface area and pore volume by adsorption of nitrogen at 77 K. The X-ray photoelectron spectroscopy (XPS) analysis was tested by ESCALAB 250 Xi spectrometer. Raman spectroscopy was performed on Renishaw INVIA micro-Raman spectroscopy system.

The morphology of transmission electronic microscope (TEM) image was collected on a Hitachi H-800 spectroscope (Japan) operating at 10 kV. Fourier Transform infrared spectroscopy (FT-IR) profiles were recorded on a Bruker Vertex 70 (German) from 400 to 4000 cm⁻¹ at a resolution of 2 cm⁻¹, equipped with a temperature- controlled attenuated total reflectance (ATR) device with a ZnSe crystal (Pike Technology). X-ray photoelectron spectroscopy (XPS) was performed on a ThermoFisher Scientific ESCALAB 250XI (USA) using monochromated Al Kalph source (150 W, 500 μm). The pass energy was 50 eV for survey, and 30 eV for high resolution scans. All binding energies were reference to the C1s peak at 284.4 eV. X-ray diffraction (XRD) patterns were recorded on a Bruker D2-phaser diffractometer (German) at 40 mA and 40 kV using Cu Kα radiation (λ = 1.54, 6.88°/min from 5 to 90°). Raman spectra were recorded on a Renishaw inVia Micro-Raman Spectroscopy System (England) equipped with charge-coupled device detector at 633 nm. Specific surface areas and pore size distributions were determined by Brunauer Emmett-Teller (BET) method on Micromeritics ASAP 2460 apparatus (USA) from nitrogen sorption isotherms collected at 77 K. The samples were degassed at 250 °C for 12 h prior to measurement.

FESEM (field-emission scanning electron microscopy, JEOL, JSM-7100F) and TEM (transmission electron microscopy, JEOL, JEM-2100F) were used to analyze the morphology and microstructure of the Co_xNi_y@C nanosheets. Raman spectra (Renishaw INVIA micro-Raman spectroscopy system) and XRD (D8 Advance X-ray diffractometer, Cu Kα radiation, λ = 1.5418 Å) was used to characterize the structure of the Co_xNi_y@C nanosheets. X-ray photoelectron spectroscopy (XPS, VGMultiLab 2000) was used to test the chemical states of elements. Adsorption of nitrogen was used to measure Brunauer–Emmett–Teller (BET) surface area using Tristar II 3020 instrument. Agilent PNA N5244A vector network analyzer (VNA) was used to test the electromagnetic parameters in the range of 2–18 GHz with coaxial wire analysis model [27 (link)]. Compressing sample and paraffin with 20% filler loading ratio made a ring with inner and outer diameter of 3.04 mm and 7.00 mm to measure.