Sta 499 f3

The crystal structures were analyzed by a D/Max-2500/PC X-ray diffractometer (XRD). The morphologies were characterized by JSM-6700F scanning electron microscopy (SEM), field emission SEM (FESEM), scanning transmission electron microscopy (STEM), JEM-2100F transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). The valence states and elements were analyzed by a ESCALAB-250Xi X-ray photoelectron spectrometer. The thermogravimetric test (TGA) was carried out with a NETZSCH STA 499 F3 device. UV–Vis absorption spectra of the adsorbed Li₂S₆ solutions were measured by an Evolution 300 UV–Vis spectrophotometer. The N₂ adsorption/desorption test by a Micromeritics ASAP 2020 analyzer was performed to measure the pore size distribution and specific surface area at 77 K. The pore size distribution and specific surface area were measured by the Barrett–Joyner–Halenda (BJH) method. The wetting angles were determined by the OCA25 contact angle measuring instrument. The molar ratio of the Ni, Fe, and Ce ions in the Ce-Ni/Fe LDH composite was analyzed with an inductive coupled plasma spectrometer.

Fourier transform infrared (FTIR) spectra were recorded by using infrared spectrophotometer (FTIR iS10, Nicolet) with a resolution of 0.4 cm⁻¹. Thermogravimetric analysis (TGA) was performed in air flow at a heating rate of 10 °C/min from 50 to 800 °C by using a TG analyzer (NETZSCH, STA 499 F3). Limiting oxygen index (LOI) was tested using a LOI tester (JF-3, Nanjing Jiangning Analytical Instrument Factory, Inc.) according to ASTMD 2863. Cone calorimeter test was performed by using an FTT cone calorimeter (Fire Testing Technology, East Grinstead) on a specimen (100 × 100 × 3 mm³) wrapped with aluminum foil at the external heat flux of 35 kW/m² according to ISO 5660-1. The morphology of char residue after cone test was observed using a field-emission scanning electron microscopy (SEM, FEI200). The structure of sintered products was analyzed by X-ray diffraction (XRD, X′Pert PRO, PANalytical, Netherlands) in reflection mode with Cu Kα radiation at 40 kV with 40 mA current (λ = 1.5406 Å). All diffraction patterns were obtained over the 2θ range of 5-80° at a scanning rate of 8°/min. Optical morphology was observed by a polarizing microscope (UPT200i, Chongqing photoelectric instrument Co., LTD). The samples in crucible were observed after sintered.