**2.4. Characterization**

The materials obtained were characterized by XRD using Siemens D500 diffractometer (Cu kα λ = 1.54 Å) at a scanning speed of 2(°2θ)/min. The specific surface area was determined by N<sup>2</sup> adsorption using the BET method on BELSORP-max equipment. The surface analysis of the materials by the AFM technique was performed in an Oxford Asylum Research Cipher AFM at room conditions with noncontact mode with a Si tip of 10 nm radius and resonance frequencies from 180 to 240 kHz. The measurements were taken in a range of 500 × 500 nm. The composites were also analyzed by XPS using Thermo Scientific K-Alpha X-ray photoelectron spectrometer, using the Al kα radiation line (1487 eV) in standard mode, with 10 scans, tip size of 400 μm, step voltage of 200.0 eV, and pass energy of 1.0 eV. All the characterization analysis was performed prior to the photocatalytic tests.
