2. CeO2 synthesis
CeO2 as co-support was prepared by redox method which is shown in Fig. 1. At first, Ce nitrate solution was made in deionized water with desired composition. In the next step, the Ce solution and H2O2 with 3:1 volume ratio were mixed. The resulted solution heated gradually and maintained for 4 h at boiling point. The aqueous solution dried at 110 °C for 24 h under air flow following by calcination at 500 °C for 4 h.