II.1.3. Preparation of the Cu-Co/ Zn-Ga catalysts – CoCuZnGa-CM

The ZnO-Ga₂O₃ support was prepared by precipitation of zinc nitrate and gallium nitrate with urea in aqueous solution. 26.32 g of Zn(NO₃)₂*6H₂O, 2.19 g of Ga(NO­₃)₃*6H₂O and 14.56 g of urea were dissolved into 400ml of water and the mixture was heated gradually to 95 °C under stirring and kept at this temperature for 4 h. After filtration and thorough washing with water, the precipitate was dried at 80 °C for 12 h, and finally calcined at 350 °C for 1 h in air. 8 g of support were prepared.

Catalysts were prepared by incipient wetness impregnation at room temperature. 5 ml of aqueous solution containing the necessary amount of Co(NO₃)₂*6H₂O and Cu(NO₃)₂*6H₂O were used for impregnation 2.148 g of support. The sample was dried at 80 °C overnight and then calcined at 350 °C for 4 h.

3 g of 15% Cu – 15% Co / 90% ZnO – 10% Ga₂O₃ catalyst were prepared.