Ceo2-Zro2

It was previously mentioned that the focus of this study is to use ceria-zirconia (CeO2-ZrO2) as the catalyst support. The approach of A. Poyraz et al. [7] to synthesize varying ratios of CeO2-ZrO2 mesoporous materials was modified and used. The modifications were the following: (a) zirconium (IV) oxynitrate hydrate was used instead of zirconium (IV) butoxide; (b) application of the method for the synthesis of CeO2-ZrO2 solid solution; and (c) physical separation of solids (filtration instead of centrifugation).

Cerium nitrate hexahydrate (Ce(NO3)3∙6H2O), zirconium (IV) oxynitrate hydrate (ZrO(NO3)2∙xH2O), 1-butanol, nitric acid (HNO3) and P123 surfactant (EO20-PPO70-PEO20) were the required chemicals. The required amounts of cerium oxide and zirconium oxide precursors (see Annex 7.2 for the calculation details) were dissolved in a solution containing respective amounts of 1-butanol, HNO3 and P123 surfactant. Then, the solution was placed in a water bath of 40 to 60 oC under magnetic stirring for further mixing. The obtained gel was placed in the oven at 120 oC for 5 h. After, the powder was washed several times with ethanol and was filtered in order to recover the solids. The solids were then dried overnight. Moreover, the dried powder was subjected to heat cycles to

Following the procedures for the bulk catalysts, the solution was stirred and was air dried for 2 to 4 days. Air-dried solution underwent the same procedure as the bulk catalysts with a final calcination temperature of 800 oC. The samples were labelled as yMo/CZ, where y represents the wt% (5, 12 or 20) concentration of molybdenum metal (present as