Jem arm200f tem stem

The loading of Au was determined by inductively coupled plasma atomic emission spectroscopy (ICPAES) using an IRIS Intrepid II XSP instrument (Thermo Electron Corporation).
Sub-angstrom-resolution high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images were obtained on the JEOL JEM-ARM200F TEM/STEM with a guaranteed resolution of 0.08 nm. Before microscopy examination, the samples were ultrasonically dispersed in ethanol and then a drop of the solution was deposited onto a copper grid coated with a thin lacey carbon film.

Powder XRD patterns of samples were recorded on a Rigaku Miniflex-600 operating at 40 KV voltage and 15 mA current with Cu Kα radiation (λ = 0.15406 nm). The SEM images were taken using a field-emission SEM (JSM-6701F, JEOL) operated at an accelerating voltage of 5 kV. The morphologies of samples were examined by TEM, using a Hitachi-7700 microscope with an accelerating voltage of 100 kV. The high-resolution TEM, HAADF-STEM, and EELS mapping were carried out by JEOL JEM-ARM200F TEM/STEM with a spherical aberration corrector working at 200 kV. The XPS was carried out on a Perkin-Elmer RBD upgraded PHI-5000C ESCA system. Raman scattering spectra were performed with a Renishaw System 2000 spectrometer using the 514.5 nm line of Ar⁺ for excitation. Elemental analysis of Co in the solid samples was detected by an Optima 7300 DV ICP-AES. The obtained adsorption–desorption isotherms were performed on a Micromeritics Tristar II 3020 M to evaluate the BET-specific surface area.

Powder X-ray diffraction (XRD, Philips, X’pert X-ray) patterns were obtained on a diffractometer with Cu Kα radiation (λ = 1.54182 Å). The spherical aberration corrected HAADF-STEM was conducted on JEOL JEM-ARM200F TEM/STEM with a spherical aberration corrector working at 200 kV. Hard X-ray absorption spectroscopy measurements were conducted at the beamline BL14W1 and BL11B of Shanghai Synchrotron Radiation Facility (SSRF, China) and the operando XAS test was performed in H₂-saturated 0.1 M KOH solution. SR-FTIR spectra were recorded at the infrared beamline BL01B of the National Synchrotron Radiation Laboratory (NSRL, China) with reflection mode and ZnSe crystal was used as the infrared transmission window (cutoff energy of ~625 cm⁻¹). The operando SR-FTIR test was carried out in H₂-saturated 0.1 M KOH solution and the background spectra were acquired at 0 V prior to each system measurement, and thus the negative peak accounts for the emergence or the increased amount of the chemicals while the positive one stands for the decrease.

GIXRD measurements were performed on a X’PertPro MPD (Panalytical) with Cu Kα radiation (λ = 0.15406 nm). The morphology of the prepared materials was observed with TEM (H-7650, Hitachi Co., Japan). High-resolution TEM, HAADF-STEM, and EELS mapping were carried out by a JEM-ARM200F TEM/STEM (JEOL Co., Japan). The defect degree of carbon was characterized by Raman spectroscopy (LABRAM HR EVO, Horiba Co, Japan). XAFS (Co K-edge) were obtained at Beamline 11B from the Shanghai Synchrotron Radiation Facility, China. Co K-edge XANES data were collected in fluorescence mode and analyzed using the ATHENA module implemented in the IFEFFIT package^{43 (link)}. A cubic spline function was used to fit the background above the absorption edge. To amplify the EXAFS oscillations in the mid-k region, k² weighting was applied, followed by a Fourier transform process for converting the data to a radial distribution (R) space with a k range of 2.5–12 Å⁻¹ at the Co K edge. High-resolution X-ray absorption spectra were collected at the Catalysis and Surface Science Endstation at the BL11U Beamline in the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China. SRPES measurements were conducted at the photoemission end-station at the BL10B Beamline in the NSRL in Hefei, China.