Ht7700 microscope

Transmission electron microscopy (TEM) images were recorded from the HT7700 microscope (JEOL, Japan) operated at 100 kV. The scanning electron microscopy (SEM) image was obtained from the SU8010 (Hitachi, Japan) at an acceleration voltage of 5 kV. Electrochemical measurements including cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were collected from the Autolab (PGSTAT302N) electrochemical workstation (Metrohm, Switzerland). A conventional three-electrode system was adopted, with bare or modified ITO as working electrode, Ag/AgCl as the reference electrode, and platinum electrode as the counter electrode. The DPV parameters were as follows: step, 5 mV; modulation time, 0.05 s; modulation amplitude, 50 mV; interval time, 0.2 s.

TEM was performed on a Hitachi HT-7700 microscope operated at 100 kV. HRTEM and EDS were performed on a JEOL JEM-F200 microscope operated at 200 kV. XRD patterns were recorded on a Rigaku SmartLab Powder X-ray diffractometer equipped with Cu Kα radiation and a D/TEX Ultra detector. ICP–MS was conducted on a NexION 350D system. XPS data were collected on a Thermo Fisher ESCALAB Xi+ spectrometer equipped with monochromatic Al Kα radiation. All binding energies in XPS studies were corrected by referring to the C 1 s binding energy at 284.5 eV. Raman spectra were collected on a Horiba Jobin Yvon LabRAM HR800 system equipped with a 532-nm laser. XAS measurements were carried out in total electron yield mode under an ultrahigh vacuum at beamline 4B9B of the Beijing Synchrotron Radiation Facility at the Institute of High Energy Physics, Chinese Academy of Sciences. Au 4f_7/2 core-level spectra were recorded for photon energy calibration.