## 3 Results and Discussion
### Physicochemical Research of Fresh Catalysts
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{4}{c}{**Textural Properties**} \\ \cline{2-4}  & **S\({}_{\text{BET}}\), m\({}^{\text{2}}\)/g** & **V\({}_{\text{pore}}\), cm\({}^{\text{3}}\)/g** & **D\({}_{\text{pore}}\), nm** \\ \hline CeMg-A-S-V & 77.9 & 0.12 & 5.1 \\ Ni/CeMg-C-S-O & 23.0 & 0.12 & 18.4 \\ Ni/CeMg-A-S-V & 13.9 & 0.05 & 9.4 \\ Ni/CeMg-A-S-O & 48.2 & 0.278 & 17.4 \\ Ni-Pd/CeMg-A-S-V & 21.1 & 0.06 & 8.3 \\ Ni/CeMg\({}_{0.5}\)-A-P-O & 34.3 & 0.104 & 7.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Textural properties of the support and as-prepared catalysts. increased value of the CeO\({}_{2}\) lattice in the A catalyst (Table 1) was due to the higher content and diameter of Ce\({}^{3+}\) (1.03 A instead of 0.92 A for Ce\({}^{4+}\)). The lattice expansion of CeO\({}_{2}\) increased the concentration of defects [51]. The peaks observed at 42.9 and 62.8\({}^{\circ}\) belonged to NiO (ICSD 24018) and/or MgO (ICSD 64929), which have similar diffraction patterns in that region. The particle sizes of NiO and CeO\({}_{2}\) decreased when cerium acetate was used as a support precursor (Figure 2). The estimation of the average size of crystalline domains from the NiO (111) phase at 37.2\({}^{\circ}\) and CeO\({}_{2}\) (200) phase at 33.2\({}^{\circ}\) according to the Debye-Scherrer equation showed that the size of the coherent scattering region (CSR) of CeO\({}_{2}\) varied from 6 to 19 nm, and for NiO, from 0 to 18 nm. Note that after calcination in vacuum at 300 \({}^{\circ}\)C and in air at 500 \({}^{\circ}\)C the samples had smaller pore and CeO\({}_{2}\)/NiO crystallite sizes (Tables 1 and 2) compared to the samples calcined at 500 \({}^{\circ}\)C in air. Like Ni catalysts, bimetallic Ni-Pd sample had a highly dispersed state of the active component (Table 1). To study the thermal stability, the samples were calcined at 500 \({}^{\circ}\)C for 2 h in air, and the XRD patterns of the samples are shown in Figure S4. The structural parameters of the samples changed with the increase of the calcination temperature, the nature of which was determined by the preparation method (Table 2). The most dispersed sample was obtained from cerium acetate by the one-stage synthesis, which was consistent with the higher thermal stability of that sample. The particle sintering could be associated with a partial destruction of the mesoporous support structure. Obviously, the sintering of nanoparticles decreased with an increase of the support thermal stability. It was noted in [52] that heat-resistant materials with a small surface area were more suitable for the CSMR reaction; when using these supports, the agglomeration of active species and the occurrence of side reactions were reduced. The part of Mg that was not included in the CeO\({}_{2}\) structure [53] could interact with nickel to form a solid solution with a \(>\) 0.417 nm (0.4177 nm for NiO and 0.4213 nm for MgO) (Table 2). The interaction of NiO with MgO was less for Ni/CeMg-A-P-O, as confirmed by the lower \(a_{\rm NiO}\) value. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{4}{c}{**500 \({}^{\circ}\)C**} & \multicolumn{4}{c}{**700 \({}^{\circ}\)C**} \\ \cline{2-9}  & \(\mathbf{a_{CO_{2}}\,\AA}\) & \(\mathbf{d_{CO_{2}}\,nm}\) & \(\mathbf{a_{NiO}\,\AA}\) & \(\mathbf{d_{NiO}\,nm}\) & \(\mathbf{a_{CO_{2}}\,\AA}\) & \(\mathbf{d_{CO_{2}}\,\AA}\) & \(\mathbf{d_{CO_{2}}\,nm}\) & \(\mathbf{a_{NiO}\,\AA}\) & \(\mathbf{d_{NiO}\,nm}\) \\ \hline Ni/CeMg-C-S-O & 5.393 & 21 & 4.20 & 17 & 5.394 & 29 & 4.196 & 40 \\ Ni/CeMg-A-S-V & 5.403 & 6 & ND 1 & ND 1 & 5.401 & 15 & 4.212 & 9 \\ Ni/CeMg-A-S-O & 5.400 & 17 & 4.17 & 14 & 5.406 & 21 & 4.185 & 19 \\ Ni-Pd/CeMg-A-S-V & 5.401 & 10 & ND 1 & ND 1 & 5.400 & 35 & 4.194 & 30 \\ Ni/CeMg-A-P-O & 5.397 & 19 & 4.17 & 18 & 5.404 & 36 & 4.185 & 40 \\ \hline \hline \end{tabular}  
* Not determined due to low intensity of the peak.  
\end{table}