Powder X-ray diffraction (XRD) measurements were performed on a Bruker D8 Advance diffractometer with Cu Kα1 radiation (λ = 1.5406 Å). The accelerating voltage and the applied current were 40 kV and 40 mA, respectively. Data were recorded at a scan rate of 0.02° 2θ s−1 in the 2θ range from 5° to 60°. Fourier transform infrared (FT-IR) spectra were recorded on a BioRad FTS 6000 spectrometer, and the samples were prepared as KBr pellets. Nitrogen adsorption–desorption isotherms were collected at a Micromeritics ASAP 2020 surface area and porosity analyzer. The sample was degassed at 413 K for 5 h and then analyzed at 77 K. The relative pressure (P/P0) range used for the calculation of BET surface area was from 0.05 to 0.35. Electron paramagnetic resonance (EPR)