*2.3. Characterization of the Catalytic Filters*

Different characterization analyses were used for the characterization of the different materials employed in this work.

The active phase in powder form was investigated using the X-ray diffraction (XRD) technique (with a microdiffractometer (Rigaku (Tokyo, Japan) D-max-RAPID), using Cu-Kα radiation), aiming at verifying the formation of the desired crystalline forms of CuFe2O4. The structured samples were characterized through:


Moreover, H2-TPR measurements were performed to investigate the reducibility of the catalyst using a sample of the catalytic SiC monolith at room temperature up to 900 ◦C

at a heating rate of 5 ◦C/min with a 5% H2/N2 flow. The concentrations of the gas stream were monitored by means of a mass spectrometer (HIDEN Analytical, Warrington, UK).

SEM images and Raman spectra (inVia Raman Microscope (Renishaw, Wotton-under-Edge, UK), equipped with a 514 nm Ar ion laser operating at 25 mW) were used for the characterization of the soot emitted by the diesel engine used for the experimental tests, as well as of the soot deposited on the catalytic filter after the deposition step.
