F200 microscope

For low-resolution TEM, a JEOL 1400 microscope was operated at 120 kV. For higher-resolution TEM, a JEOL F200 microscope was operated at 200 kV. During imaging, magnification, focus, and tilt angle were varied to yield information about the crystal structure and super structure of the particle systems. To prepare the dispersed nanocrystals for imaging, we drop cast 10 μL of a dilute (~0.1 mg/mL) dispersion of nanocrystals in hexane on a carbon-coated TEM grid (EMS). The grid was dried under vacuum for 1 h prior to imaging.

Samples for HR(S)TEM measurements
are prepared using a focused ion beam lift-out technique in an FEI
Helios Nanolab 660. HRTEM images have been acquired at a FEI Titan3
80-300 image-corrected microscope. EDX measurements have been performed
at a JEOL F200 microscope operated at 200 kV using a 100 mm² window-less silicon drift detector. The EDX spectra have been denoised
with principal component analyses (PCA) using 20 components.^{48 (link)}

SEM images were taken by a ZEISS SUPRA55 microscope. A JEOL F200 microscope was used to take the TEM images. AFM images were obtained by Bruker Dimension FastScan microscope. Aberration corrected STEM imaging and EELS mapping were acquired from a Nion HERMES-100 under 100 kV with a 30 mrad convergence angle. The enlarged STEM-BF image is denoised by low-psss filtering. Cu valence state analysis was performend by multiple linear least squares (MLLS) fitting in the 920–960 eV energy-loss range. The processed EELS data has been calibrated along the energy-loss axis to much the standard data⁵⁶ , as the as-acquired spectra deviate slightly due to the small non-linearity of the energy dispersion at the two ends of the spectrometer prism. XPS spectra (ESCALAB 250Xi, Thermo Fisher Scientific Inc., USA) was used to investigate chemical compositions and elemental oxidation states of the catalysts. Raman spectra were obtained from the Raman spectrometer (Horiba, Olympus microscope) with a 532 nm laser. GI-XRD patterns were obtained by a Panalytical Empyrean X-ray diffractometer. Gas products were analyzed by a Shimadzu GC 2030 gas chromatograph. Liquid products were analyzed by a NMR spectroscopy (AVANCE III 600 M, Bruker).