CexTi1-xO2 Mixed Oxides Supported CuO Catalyst for NO Reduction by CO

CexTi1-xO2 mixed oxides of different mole ratios (x=0, 0.1, 0.2～0.9, 1.0) were prepared by co-precipitation of TiCl4 with Ce(NO3)3 and then loaded with different amounts of CuO. The effects of CuO on NO+CO reaction were investigated, and the structure and reductive properties of various CuO/CexTi1-xO2 were characterized by the methodologies of BET, TPR and XRD. The results show that different Ce/Ti mole ratios and calcination temperatures induce changes of structure and reductive properties of the CexTi1-xO2 mixed oxides. When x=0.1～0.5, amorphous CeTi2O6 phase mainly forms at 650 ℃ compared to the formation of CeTi2O6 which crystallizes at 800 ℃. When x＞0.6, some TiO2 enters the CeO2 lattice and a CeO2-TiO2 solid solution is formed. The activity of 6%CuO/CexTi1-xO2 calcined at 650 ℃ is largely affected by the x values, which is the highest when x=0.3, 0.4 and 0.9. The NO conversion reaches 70% at a reaction temperature of 150 ℃. By comparison, the x values have little effect on the activity of 6%CuO/CexTi1-xO2 calcined at 800 ℃. There are strong interactions between CuO and CeTi2O6, I.e., formation of the CeTi2O6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi2O6 reduction peak temperature from 600 to 300 ℃.