2.3. Electrochemical properties
All electrochemical experiments were performed in the electrolytic cell consisted of a glassy carbon (GC) or a modified GC working electrode (3 mm diameter, CHI), a platinum wire counter electrode and a saturated calomel reference electrode (SCE) on a Model CHI 660 E electrochemical workstation. All potentials were referred to a SCE. The AGN 205327 values of the solutions were determined with a PHS-3 C pH meter.
Fourier transform infrared spectroscopy (FT-IR) spectra of the samples were measured on a Cary 610/670 microscope (Varian, US). Scanning electron microscopy (SEM) was examined on a field-emission scanning electron microanalyzer (Hitachi S-4800, Japan). The electron spin resonance (ESR) measurements were carried out using a Bruker A300 spectrometer operated in X-band (9.863 GHz). X-ray photoelectron spectroscopy (XPS) measurements were carried out with an ESCALAB 250 Xi photoelectron spectrometer using Al Kα radiation (Thermo-Fisher Scientific, US).