*3.3. Characterization of the Catalysts*

The morphology of the catalysts was characterized by Scanning Electron Microscopy (SEM), using a Hitachi S-3000N instrument (Westford, MA, USA), equipped with a EDX Quantax EDS X-Flash 6I30 Analyzer, and by High Resolution Transmission Electron Microscopy (HRTEM), using a JEOL 3000F (Peabody, MA, USA). XPS measurements were performed on an ESCALAB 220i-XL spectrometer (East Grinstead, United Kingdom), using the non-monochromated Mg Kα (1253.6 eV) radiation of a twin-anode, operating at 20 mA and 12 kV in the constant analyzer energy mode, with a PE of 40 eV. Brunauer Emmett Teller (BET) specific areas were measured using a Micromeritics ASAP 2020, according to N<sup>2</sup> adsorption isotherms at 77 K. Raman spectra were collected using a DXR Raman Microscope (Thermo Scientific, Waltham, MA, USA), employing a 532 nm laser source at 5 mW power and a nominal resolution of 5 cm−<sup>1</sup> . Diffuse reflectance measurements were carried out on a Perkin Elmer Lambda 365 UV-Vis spectrophotometer (Perkin Elmer, Waltham, MA, USA), equipped with an integrating sphere. The bandgap value was obtained from the plot of the Kubelka–Munk function versus the energy of the absorbed light [67]. X-ray powder diffraction patterns (XRD) were collected using a Bruker D8 Discover X-ray Diffractometer (Madison, WI, USA), in Bragg–Brentano goniometer configuration. The X-ray radiation source was a ceramic X-ray diffraction Cu anode tube type Empyrean of 2.2 kW. XRD diffractograms were recorded in angular range of 30–75◦ at 1◦ min−<sup>1</sup> , operating at 40 kV and 40 mA.
