## 2 Materials and Methods
### Methods for Preparing Catalysts  
X\({}_{0.2}\)Ce\({}_{0.4}\)Mg\({}_{0.4}\)O\({}_{1.4}\) catalyst samples (X = Ni, Ni\({}_{0.97}\)P\({}_{0.03}\)) were prepared by the SGT method assisted with Pluronic F127 by varying the support precursor (cerium acetate and chloride); the method of introducing nanoparticles was as follows: a S-series, in which nanoparticles were incorporated at the stage of sol formation (one-stage synthesis), and a P-series, in which nanoparticles were obtained by the polyol technique (PT) in the presence of a support. The nickel and palladium concentrations were 10 wt.% and 0.5%, respectively. Colloidal solutions of Ni-Pd nanoparticles (molar ratio Pd/Ni = 0.03) were synthesized by PT. Polyvinylpyrrolidone (PVP) was dissolved in anhydrous ethylene glycol, a calculated amount of Ni(CH\({}_{3}\)COO)\({}_{2}\cdot\)4H\({}_{2}\)O was added, and the mixture was heated to 80 \({}^{\circ}\)C for 2 h. The calculated amount of Pd(CH\({}_{3}\)COO)\({}_{2}\) was dissolved in 1,4-dioxane with vigorous stirring for 2 h. Then, the first solution was cooled to 0 \({}^{\circ}\)C in an ice bath and the solution of Pd precursor was added thereto while stirring. A 1 M NaOH solution was added to adjust the pH of the mixture to 9-10. The resulting solution was heated for 2 h.  
In the S-series, the colloid precipitate Ni-Pd or Ni(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O was dissolved by stirring in ethanol. Then, Pluronic F127 dissolved in ethanol was added. A solution of CeCl\({}_{2}\cdot\)7H\({}_{2}\)O or Ce (CH\({}_{3}\)COO)\({}_{2}\cdot\)15H\({}_{2}\)O and Mg(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O in ethanol and water was added under stirring. The molar ratio of the reagents in CeO\({}_{2}\) was 0.5 CeCl\({}_{2}\cdot\)7H\({}_{2}\)O (Ce(CH\({}_{3}\)COO)\({}_{2}\cdot\)1.5H\({}_{2}\)O):0.5 Mg(NO\({}_{3}\))\({}_{2}\cdot\)0.009F127:10H\({}_{2}\)O:25C\({}_{2}\)H\({}_{5}\)OH. The sol prepared from cerium acetate was placed in an oven at 40 \({}^{\circ}\)C and 50% humidity for 2 days until gel formation, then dried for 1 day at 60 \({}^{\circ}\)C and 1 day at 100 \({}^{\circ}\)C. To remove the surfactant, the samples were calcined in two ways: without access to air and in air. In the first case, the sol was dried in a vacuum oven at 300 \({}^{\circ}\)C and a pressure of 13 mbar for 2 h at a heating rate (HR) of 1 \({}^{\circ}\)C/min. The sol (prepared from both chloride and cerium acetate) was transferred to an oven, the furnace temperature was increased to 200 \({}^{\circ}\)C at an HR of 20 \({}^{\circ}\)C/min; then, the temperature was increased to 500 \({}^{\circ}\)C at an HR of 1 \({}^{\circ}\)C/min; at that temperature the samples were heated for 2 h to stabilize the mesoporous structure. In the P-synthesis, the prepared support was added to a solution of PVP and Ni(CH\({}_{3}\)COO)\({}_{2}\)-4H\({}_{2}\)O in ethylene glycol. The supports were prepared by the SGT method. Then, the suspension was cooled to 0 \({}^{\circ}\)C in an ice bath and the pH of the mixture was adjusted to 9-10 with a 1 M NaOH solution. The resulting solution was heated for 2 h with vigorous mixing. The composition of the mixture was 0.5 Ce(CH\({}_{3}\)COO)\({}_{2}\)-1.5H\({}_{2}\)O: 0.5 Mg(NO\({}_{3}\))\({}_{2}\):0.009 F127:10H\({}_{2}\)O:25C\({}_{2}\)H\({}_{5}\)OH. The sol was transferred to a vacuum oven, heated to 200 \({}^{\circ}\)C for 2 h; the HR was 1 \({}^{\circ}\)C/min. Then, the catalyst was placed in an oven, heated to 200 \({}^{\circ}\)C with an HR of 20 \({}^{\circ}\)C/min. The temperature was increased to 500 \({}^{\circ}\)C; the HR was 1 \({}^{\circ}\)C/min; at that temperature, the sample was heated for 4 h to stabilize the mesoporous structure. The samples were marked in accordance with the procedure for their synthesis: the first letter denoted the support precursor, where \"A\" and \"C\" corresponded to acetate and cerium chloride, and \"S\" and \"P\" corresponded to samples obtained by one-stage and polyol methods, respectively.