Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effe...Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 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/Ce x Ti 1- x O 2 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 Ce x Ti 1- x O 2 mixed oxides. When x =0.1～0.5, amorphous CeTi 2O 6 phase mainly forms at 650 ℃ compared to the formation of CeTi 2O 6 which crystallizes at 800 ℃. When x >0.6, some TiO 2 enters the CeO 2 lattice and a CeO 2 TiO 2 solid solution is formed. The activity of 6%CuO/Ce x Ti 1- x O 2 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/Ce x Ti 1- x O 2 calcined at 800 ℃ . There are strong interactions between CuO and CeTi 2O 6, i.e., formation of the CeTi 2O 6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi 2O 6 reduction peak temperature from 600 to 300 ℃.展开更多
Ce1-xBixO2-δ （x = 0.00, 0.03, 0.05, 0.07, 0.10, 0.15, 0.30） solid solutions were synthesized via a hydrothermal method. The structure, spectra and electrochemical transport properties of the samples were characteri...Ce1-xBixO2-δ （x = 0.00, 0.03, 0.05, 0.07, 0.10, 0.15, 0.30） solid solutions were synthesized via a hydrothermal method. The structure, spectra and electrochemical transport properties of the samples were characterized systematically. The powder X-ray diffraction analysis showed that all of the doped samples exhibited single phase fluorite structure. The particle sizes decreased from 18 to 9 nm and the lattice parameters increased gradually with the dopant content increasing from x = 0.03 to x = 0.30. The Bi^3＋ doping also induced the F2g Raman peak to shift from 463 to 455 cm^-1, and caused a red shift of the band gap energies calculated from UV-Vis spectra. The impedance plots at different temperature demonstrated that the boundary resistance was much larger than the grain resistance, and two activation energy values were obtained in different temperature range.展开更多
文摘Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 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/Ce x Ti 1- x O 2 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 Ce x Ti 1- x O 2 mixed oxides. When x =0.1～0.5, amorphous CeTi 2O 6 phase mainly forms at 650 ℃ compared to the formation of CeTi 2O 6 which crystallizes at 800 ℃. When x >0.6, some TiO 2 enters the CeO 2 lattice and a CeO 2 TiO 2 solid solution is formed. The activity of 6%CuO/Ce x Ti 1- x O 2 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/Ce x Ti 1- x O 2 calcined at 800 ℃ . There are strong interactions between CuO and CeTi 2O 6, i.e., formation of the CeTi 2O 6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi 2O 6 reduction peak temperature from 600 to 300 ℃.
基金financially supported by the National Natural Science Foundations of China(No.51371094,51161015)the Inner Mongolia Natural Science Foundation(No.2013MS0806)
文摘Ce1-xBixO2-δ （x = 0.00, 0.03, 0.05, 0.07, 0.10, 0.15, 0.30） solid solutions were synthesized via a hydrothermal method. The structure, spectra and electrochemical transport properties of the samples were characterized systematically. The powder X-ray diffraction analysis showed that all of the doped samples exhibited single phase fluorite structure. The particle sizes decreased from 18 to 9 nm and the lattice parameters increased gradually with the dopant content increasing from x = 0.03 to x = 0.30. The Bi^3＋ doping also induced the F2g Raman peak to shift from 463 to 455 cm^-1, and caused a red shift of the band gap energies calculated from UV-Vis spectra. The impedance plots at different temperature demonstrated that the boundary resistance was much larger than the grain resistance, and two activation energy values were obtained in different temperature range.
