D max 2400 x ray powder diffractometer

Elemental analyses of C, H, and N was performed on a Vario EL III elemental analyzer. Hydrogen NMR spectra were measured on a Bruker-400 spectrometer with Me₄Si as an internal standard. X-ray powder diffraction (XRD) patterns of the PCPs were recorded on a Rigaku D/max-2400 X-ray powder diffractometer (Japan) with Cu-Kα (λ = 1.5405 Å) radiation. Thermogravimetric analysis (TGA) was carried out at a ramp rate of 5 °C/min in a nitrogen flow with a Mettler-Toledo TGA/SDTA851 instrument. FT-IR spectra were recorded using KBr pellets on a JASCO FT/IR-430 spectrometer. Gas adsorption isotherms were obtained on a BELSORP-max adsorption instrument (BEL Japan Inc.) using a volumetric technique. The initial outgassing of the sample was carried out under high vacuum (P < 10⁻² Pa, T = 120 °C) for 32 h to remove solvated water molecules. The CO₂ adsorption isotherms for desolvated compounds were collected in a relative pressure range from 10 to 1.0 × 10⁵ Pa.

CB samples of approximately 0.5 g were degassed for 3 h at 125 °C. The surface morphology of the CB samples was analyzed in a JSM-6510LV scanning electron microscope (JEOL Ltd., Tokyo, Japan) at a 20 kV. The BET-SSA and pore size analysis were determined using N₂ as the adsorbate at 77 K and relative pressure of 0.05–0.20, for which a V-Sorb 2800P BET-SSA and pore size analyzer (Gold APP Instrument Co., Ltd., Beijing, China) was used. All CB samples were scanned with an Escalab 250 Xi X-ray photoelectron spectrometer (Thermo Fisher Scientific Co., Ltd., Waltham, MA, USA) to investigate the chemical state of the main elements and the functional groups on the surface. The chemical bonds were identified by published references and the National Institute of Standards and Technology database (https://srdata.nist.gov/xps/). The mineral species of the CB samples were identified using a D/max2400 X-ray powder diffractometer (Rigaku Co., Ltd., Wilmington, NC, USA) at a 0.02 scan step size, 2 deg·min⁻¹ scan speed, 0.15 receiving slit width, 30–40 kV, and 30–40 mA. The surface functional groups of CB samples were measured with KBr pellet methods by infrared spectra analysis using a Vertex70 FTIR spectrometer (Bruker Co., Ltd., Billerica, USA) for 16 scans over a range of 400–4000 cm⁻¹ with a resolution of 2 cm⁻¹.