4.5. Structural characterizations
The morphology of the samples was observed by SEM JEOL S-4800 using an
accelerating voltage of 10 kV and TEM JEM-F200 using an accelerating
voltage of 80 kV, which were shown in SEM, TEM, HRTEM, SAED and HAADF
images. Furthermore, the preferred growth orientation and crystallinity
of the samples were shown by the XRD images provided by the Bruker D8
Advance X-ray diffractometer applying Cu Kα radiation (λ = 0.154 nm).
The element distribution/composition and electron population were
characterized by TEM mapping, EDS, soft XAS and XPS. Among them, the
photoemission end-station (BL10B beamline) of soft XAS was located at
the in the National Synchrotron Radiation Laboratory (NSRL) in Hefei,
China. In addition, the soft XAS data was normalized by the µ(E) energy
mode in Athena software. The device model for XPS has been selected as
ESCALAB250Xi with Mg Kα (1486.6 eV) as the radiation source. In
addition, the catalyst used to test the potential-dependent
quasi-in-situ XPS needs to be pretreated for 8 min under the
corresponding potential environment.