2.4.3. SEM-EDX Analysis

SEM images have shown that, in this experiment, the carbon is under the form of filaments of varying diameters. For CNF-DR, the diameter range is 15–50 nm (Figure 18) and for CNF-CC it is 25–75 nm (Figure 19). Using backscattered electron imaging (Figure 20), we can see that the metal particles are located on the top of the nanofilaments.

**Figure 18.** SEM analysis of carbon deposited on Ni-UGSO 13% after DR reaction at 650 ◦C for 2 h TOS.

**Figure 19.** SEM analysis of carbon deposited on Ni-UGSO 13% after the CC reaction at 750 ◦C for 2 h TOS.

**Figure 20.** SEM analysis (using backscattered electron imaging) of carbon deposited on Ni-UGSO 13% after DR reaction at 650 ◦C for 2 h TOS.

The EDX images presented in Figures 21 and 22 give a chemical analysis of the spent catalyst and carbon deposited. We notice on the spectrum that the peaks of carbon are intense for both reactions, which proves the existence of carbon corresponding to CNF, as we can see on the SEM images.

**Figure 21.** EDX analysis of carbon deposited on Ni-UGSO 13% after the DR reaction at 650 ◦C for 2 h TOS.

**Figure 22.** EDX analysis of carbon deposited on Ni-UGSO 13% after the CC reaction at 750 ◦C for 2 h TOS.
