Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts(TWCs).However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is stil...Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts(TWCs).However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is still a challenge.In this paper,the cerium zirconium solid solution was prepared by a coprecipitation-hydrothermal method,and the effects of the ammonia concentration on their structures and redox properties were investigated.The results show that when the ammonia concentration is 0.8 mol/L,the aged sample(1100℃/10 h)of cerium zirconium solid solution has the highest specific surface area of 23.01 m^(2)/g.Additionally,the increase of ammonia concentration improves the uniformity of phase compositions and increases the oxygen vacancies.When the ammonia concentration reaches 0.4 mol/L,the cerium zirconium solid solution exhibits the best redox activity,with the lowest reduction temperature of 565℃.Therefore,increasing ammonia concentration in the hydrothermal treatment is beneficial to the thermal stability and redox performance of cerium zirconium solid solution.展开更多
A solution-solid method is developed to construct cerium phosphate （CePO4） nanofibers. Tetraphosphoric acid formed the condensed linear polyphosphate （PnO3n＋1）^（n＋2）- before reacting with cerium carbonate （Ce...A solution-solid method is developed to construct cerium phosphate （CePO4） nanofibers. Tetraphosphoric acid formed the condensed linear polyphosphate （PnO3n＋1）^（n＋2）- before reacting with cerium carbonate （Ce2（CO3）3） powder, which was favourable for one dimensional CePO4 nanofibers forming. The growth mechanism was proposed based on solution-solid process. CePOa nanofibers display strong UV luminescence emission and weak blue emission.展开更多
A series of Ti1-xZrxO2 materials were synthesized through a multistep sol-gel process. The structural characteristics were investigated using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Ram...A series of Ti1-xZrxO2 materials were synthesized through a multistep sol-gel process. The structural characteristics were investigated using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Raman measurements. The experimental results showed that a solid solution could be obtained at low Zr/（Ti＋Zr） molar ratios （x ≤0.319）. Raman measurements exhibited that the presence of zirconium in the solid solutions greatly retarded the amorphous-anatase and anatase-rutile transitions. The diffuse reflectance UV-Vis spectra revealed that the bandgap of the solid solution was enlarged gradually with the increment of incorporated zirconium content. The Ti1-xZrxO2 solid solutions exhibited higher photocatalytic activity than pure TiO2 for the degradation of 4-chlorophenol aqueous solution.展开更多
基金Project supported by the National Key Research and Development Program(2017YFC0211002).
文摘Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts(TWCs).However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is still a challenge.In this paper,the cerium zirconium solid solution was prepared by a coprecipitation-hydrothermal method,and the effects of the ammonia concentration on their structures and redox properties were investigated.The results show that when the ammonia concentration is 0.8 mol/L,the aged sample(1100℃/10 h)of cerium zirconium solid solution has the highest specific surface area of 23.01 m^(2)/g.Additionally,the increase of ammonia concentration improves the uniformity of phase compositions and increases the oxygen vacancies.When the ammonia concentration reaches 0.4 mol/L,the cerium zirconium solid solution exhibits the best redox activity,with the lowest reduction temperature of 565℃.Therefore,increasing ammonia concentration in the hydrothermal treatment is beneficial to the thermal stability and redox performance of cerium zirconium solid solution.
基金the Jiangsu Province College Natural Science Foundation (No. 08KJD150003)ChangzhouYoung Foundation (No. CQ2008011)Application Basis Research Program of Jiangsu Teachers University of Technology (No. KYY08001) for financial support
文摘A solution-solid method is developed to construct cerium phosphate （CePO4） nanofibers. Tetraphosphoric acid formed the condensed linear polyphosphate （PnO3n＋1）^（n＋2）- before reacting with cerium carbonate （Ce2（CO3）3） powder, which was favourable for one dimensional CePO4 nanofibers forming. The growth mechanism was proposed based on solution-solid process. CePOa nanofibers display strong UV luminescence emission and weak blue emission.
基金Project supported by the National Natural Science Foundation of China （Nos. 50221201, 90301010, 50502033, 50472035）, the Chinese Academy of Sciences and the Natural Science Foundation of Tianjin City （Grant No. 043612411）.
文摘A series of Ti1-xZrxO2 materials were synthesized through a multistep sol-gel process. The structural characteristics were investigated using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Raman measurements. The experimental results showed that a solid solution could be obtained at low Zr/（Ti＋Zr） molar ratios （x ≤0.319）. Raman measurements exhibited that the presence of zirconium in the solid solutions greatly retarded the amorphous-anatase and anatase-rutile transitions. The diffuse reflectance UV-Vis spectra revealed that the bandgap of the solid solution was enlarged gradually with the increment of incorporated zirconium content. The Ti1-xZrxO2 solid solutions exhibited higher photocatalytic activity than pure TiO2 for the degradation of 4-chlorophenol aqueous solution.
