Thermo escalab 250

To further detect the composition at different depths of the corrosion surface, the XPS of the prepared specimens was carried out by K-Alpha X-ray photoelectron spectrometer (thermo escalab 250, Thermo Fisher Scientific, Gloucester, UK). Prior to XPS test, the specimens were treated in deionized water and dried using a vacuum oven [33 (link)]. The Al Ka X-ray source were used to motivate the high-resolution photoelectron of Cu2p and O1s, while the output data were analyzed by the XPS PEAK 1 software (Version 4.1).

Fourier transform infrared (FTIR) spectroscopy was conducted using the Nicolet iS50 to characterize the chemical structure. X-ray diffraction (XRD) patterns were observed using the Rigaku MiniFlex 600 (SCINCO CHINA, Shanghai, China) with Cu-Kα radiation to analyze the crystal structure. Scanning electron microscopy (SEM) images were obtained using the Hitachi field emission scanning electron microscope, and transmission electron microscopy (TEM) images were collected through the JEM-2100 to examine the morphology and structure of the samples. X-ray photoelectron spectroscopy (XPS) was conducted using the Thermo ESCALAB 250 (Thermo Fisher Scientific, Shanghai, China) with an X-ray Al Kα source to analyze the bonding state.

Field-emission scanning electron microscope (FE-SEM, FEI, Hillsboro, OR, USA) measurements were collected on an FEG Quanta 200 FEI and applied to study the surface structures and composition of the samples. X-ray diffraction (XRD) spectroscopy was carried out on an X-ray diffractometer (Rigaku 2550, Rigaku, Tokyo, Japan,) using Cu Kα radiation to record the crystallographic phases of the obtained products. Resonant Raman spectra were conducted on a Renishaw in Via spectrometer with the excitation source of a 514-nm laser. The sample composition and elemental state were measured using X-ray photoelectron spectroscopy (XPS) (Thermo ESCALAB 250, Thermo Fisher Scientific, Waltham, Ma, USA) with Al Kα as the excitation source.

In this study, the CuO NWs were fabricated via SMAT-assisted thermal oxidation method. Briefly, copper plates (99.99%) with size of 20 × 20 × 5 mm were cleaned by alcohol to remove surface impurities including grease and other organics. The copper plates were then treated by an SMAT process in which millimeter-size steel balls were acoustically driven to bombard the Cu surface randomly and in all directions to generate nanocrystalline Cu [28 (link)]. After drying in N₂ atmosphere, the clean samples were heated in a horizontal tube at 500°C in pure O₂ atmosphere (375 Torr) for 2.5 h. The morphologies and structure of the as-prepared CuO NWs were characterized by scanning electron microscopy (SEM, FEI Quanta 200 FEG, FEI, Hillsboro, OR, USA), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM, JEOL JEM-2010 at 200 kV, JEOL, Akishima-shi, Tokyo, Japan), X-ray diffraction (XRD, Rigaku D/Max-γB, with Cu Kα radiation, Rigaku Corporation, Tokyo, Japan) and X-ray photoelectron spectroscopy (XPS, ThermoESCALAB250, Thermo Fisher Scientific, Waltham, MA, USA).

X-ray photoelectron spectroscopy (XPS) was carried out on a Thermo ESCALAB 250 X-ray photoelectron spectroscopy(Thermo Fisher Scientific, Waltham, MA, USA) using Al Ka (1486.6 eV) excitatior with pass energy of 20 eV at a reduced power of 150 W. The samples were attached to the spectrometer probe with double-sided adhesive tape, and the X-ray beam was 500 μm.