Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau...Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.展开更多
Ce-doped nanosized ZnO desulfurizer was prepared by homogeneous precipitation,and its desulfurization efficiency at ambient temperature was investigated through dynamic experiments.The results showed that the desulfur...Ce-doped nanosized ZnO desulfurizer was prepared by homogeneous precipitation,and its desulfurization efficiency at ambient temperature was investigated through dynamic experiments.The results showed that the desulfurization activity of nanosized Ce-ZnO had improved greatly,compared to nanosized ZnO desulfurizer.Nanosized Ce-ZnO desulfurizer was characterized by XRD,TPD-MS,XPS,and TEM.The research results indicated that doping Ce decreased the particle size of the nanosized ZnO desulfurizer and ZnS was the principal desulfurization product.There were adsorption complexes of HS and S on the surface of desulfurizer as well.Only a small amount of vapor appeared in the tail gas on the condition of meeting the precision of desulfurization.展开更多
A series of Ce-doped MnOx/TiO2 catalysts were prepared by impregnation method and used for catalytic oxidation of NO in the presence of excess O2. The sample with the Ce doping concentration of Ce/Mn=l/3 and calcined ...A series of Ce-doped MnOx/TiO2 catalysts were prepared by impregnation method and used for catalytic oxidation of NO in the presence of excess O2. The sample with the Ce doping concentration of Ce/Mn=l/3 and calcined at 300 ℃ shows a superior activity for NO oxidation to NO2. On Ce(1)Mn(3)Ti catalyst, 58% NO conversion was obtained at 200 ℃ and 85% NO conversion at 250 ℃ with a GHSV of 41000 h-1, which was much higher than that over MnOx/TiO2 catalyst (48% at 250 ℃). Characterization results implied that the higher activity of Ce(1)Mn(3)Ti could be attributed to the enrichment of well-dispersed MnO2 on the surface and the abundance of Mn3+ and Zi3+ species. The addition of Ce into MnO2/TiO2 could improve oxygen storage capacity and facilitate oxygen mobility of the catalyst as shown by PL and ESR, so that its activity for NO oxidation could be enhanced. The effect of H2O and SO2 on the catalyst activity was also investigated.展开更多
Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO c...Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO catalyst showed enhanced activity and diphenyl carbonate selectivity compared with the Pd/CeO2 catalyst.The catalytic performance of Pd/CZO was influenced by the calcination temperature of the CZO support.X-ray diffraction,scanning electron microscopy,N2 adsorption–desorption measurements,X-ray photoelectron spectroscopy and H2 temperature-programmed reduction measurements were used to investigate the effects of Zr doping and calcination temperature.The catalytic performance of Pd/CZO and Pd/CeO2 for the oxidative carbonylation of phenol was affected by several factors,including the specific surface area,Ce^3+and/or oxygen vacancy content,oxygen species type and Pd(II)content of the catalyst.All these properties were influenced by Zr doping and the calcination temperature of the CZO support.展开更多
Cerium-doped MCM-48 molecular sieves were synthesized hydrothermally and characterized by X-ray diffraction, nitrogen adsorption, transmission electron microscope, FT-IR spectroscopy, UV-visible spectroscopy, and Rama...Cerium-doped MCM-48 molecular sieves were synthesized hydrothermally and characterized by X-ray diffraction, nitrogen adsorption, transmission electron microscope, FT-IR spectroscopy, UV-visible spectroscopy, and Raman spectroscopy. The results showed that all the samples held the structure of MCM-48, and Ce could enter the framework of MCM-48. However, when Ce/Si molar ratio in the sampies was high (0.04 or 0.059), there were CeO2 crystallites as secondary phase in the extraframework of MCM-48. Ce-doped MCM-48 was a very efficient catalyst for the oxidation of cyclohexane in a solvent-free system with oxygen as an oxidant. In the conditions of 0.5 MPa 02 and 413 K for 5 h, the conversion of cyclohexane was 8.1% over Ce-MCM-48-0.02, the total selectivity of cyclohexanol and cyclohaxnone was 98.7%. With an increase of Ce content, the conversion of cyclohexane and the selectivity to cyclohexanol decreased somewhat, but the selectivity to cyclohexanone increased.展开更多
Ce-doped titanium oxide nanoparticles were investigated in the paper. The surface structures of undoped and Ce-doped TiO2 nanoparticles were observed by scanning tunneling microscopy (STM). The experimental results ...Ce-doped titanium oxide nanoparticles were investigated in the paper. The surface structures of undoped and Ce-doped TiO2 nanoparticles were observed by scanning tunneling microscopy (STM). The experimental results of scanning tunneling spectroscopy (STS) show that the surface electronic structures of TiO2 nanoparticles are modified by introducing new electronic states in the surface band gap through cerium ion doping. The results are discussed in terms of the influence of doping concentration on the surface band gap of TiO2.展开更多
ZnO nanorods were synthesized using the sol-gel method, and the effects of annealing temperature and Ce doping on the morphologies and optical properties of ZnO nanostructures were investigated in detail. The XRD meas...ZnO nanorods were synthesized using the sol-gel method, and the effects of annealing temperature and Ce doping on the morphologies and optical properties of ZnO nanostructures were investigated in detail. The XRD measurements showed that the as-synthesized ZnO nanostructures had a hexagonal wurtzite structure. SEM images showed that uniform nanorods formed at 900 °C. Photoluminescence measurements showed an ultraviolet emission peak and a relatively broad visible light emission peak for the samples sintered at different temperatures. The UV emission peak bathochromically shifted when the annealing temperature rose from 850 to 1000 °C. Ce doping decreased the synthesized temperature of the ZnO nanorods to 500 °C, and the UV peaks hypsochromically shifted.展开更多
In order to develop a novel electric light source, the doped high-silica glass was studied on the preparation and spectroscopic properties. ne porous glasses were made firstly and were then immersed in the solution co...In order to develop a novel electric light source, the doped high-silica glass was studied on the preparation and spectroscopic properties. ne porous glasses were made firstly and were then immersed in the solution containing Ce ion. Thereafter, the high-silica glasses containing Ce ion were prepared by sintering the porous preform. The spectroscopic properties were studied before and after heath treatment in H-2. The experimental results indicate that the suitable temperature schedules are the most important to prepare doped high-silica glass. The study of the spectra shows that Ce ion can be reduced to low valence state when it is heat-treated in H-2. It can be used to adjust the UV cut-off wavelength of high-silica glass by changing the valence state of Ce ion.展开更多
Thispaperisconcerned withthe preparation ofcerium doped yttrium iron garnet which areknown to be an oxide withlarge magneto opticaleffect. Usingtheimproved flux method wesuccessfully grew the bulksinglecrystalsofiron...Thispaperisconcerned withthe preparation ofcerium doped yttrium iron garnet which areknown to be an oxide withlarge magneto opticaleffect. Usingtheimproved flux method wesuccessfully grew the bulksinglecrystalsofiron garnet doped by Ce 3 + ions with maximum substitution upto0 349. Here weinvestigatedthedifferentcomposition ofsolution for maxi mum Ce3 + substitution. Thespectra ofthe Faraday rotation andtheoptical absorption were measured inthenearinfrared region fordifferentCe3 + ionsdopediron garnets. The Cesub stitution prominentlyenhancesthe Faradayeffect,andthe Yb and Euionssubstitutefor Yinthe dodecahedralsitesof YIGcanincreasetheconcentration of Ce3 + ions, depresstheforma tion of nonmagnetic Ce4 + ionsbythechargecompensation.展开更多
基金support from the Free Exploration Project of Frontier Technology for Laoshan Laboratory(No.16-02)the National Natural Science Foundation of China(Nos.22072015 and 21927811)。
文摘Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.
基金Project supported by the National Natural Science Foundation of China(50478026)
文摘Ce-doped nanosized ZnO desulfurizer was prepared by homogeneous precipitation,and its desulfurization efficiency at ambient temperature was investigated through dynamic experiments.The results showed that the desulfurization activity of nanosized Ce-ZnO had improved greatly,compared to nanosized ZnO desulfurizer.Nanosized Ce-ZnO desulfurizer was characterized by XRD,TPD-MS,XPS,and TEM.The research results indicated that doping Ce decreased the particle size of the nanosized ZnO desulfurizer and ZnS was the principal desulfurization product.There were adsorption complexes of HS and S on the surface of desulfurizer as well.Only a small amount of vapor appeared in the tail gas on the condition of meeting the precision of desulfurization.
基金supported by the National Natural Science Foundation of China (Grant No. 51078185)
文摘A series of Ce-doped MnOx/TiO2 catalysts were prepared by impregnation method and used for catalytic oxidation of NO in the presence of excess O2. The sample with the Ce doping concentration of Ce/Mn=l/3 and calcined at 300 ℃ shows a superior activity for NO oxidation to NO2. On Ce(1)Mn(3)Ti catalyst, 58% NO conversion was obtained at 200 ℃ and 85% NO conversion at 250 ℃ with a GHSV of 41000 h-1, which was much higher than that over MnOx/TiO2 catalyst (48% at 250 ℃). Characterization results implied that the higher activity of Ce(1)Mn(3)Ti could be attributed to the enrichment of well-dispersed MnO2 on the surface and the abundance of Mn3+ and Zi3+ species. The addition of Ce into MnO2/TiO2 could improve oxygen storage capacity and facilitate oxygen mobility of the catalyst as shown by PL and ESR, so that its activity for NO oxidation could be enhanced. The effect of H2O and SO2 on the catalyst activity was also investigated.
基金supported by the National Natural Science Foundation of China(21776057)the Natural Science Foundation of Tianjin City(Nos.17JCYBJC20100,18JCYBJC21500)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Hebei Province(CL201605)。
文摘Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO catalyst showed enhanced activity and diphenyl carbonate selectivity compared with the Pd/CeO2 catalyst.The catalytic performance of Pd/CZO was influenced by the calcination temperature of the CZO support.X-ray diffraction,scanning electron microscopy,N2 adsorption–desorption measurements,X-ray photoelectron spectroscopy and H2 temperature-programmed reduction measurements were used to investigate the effects of Zr doping and calcination temperature.The catalytic performance of Pd/CZO and Pd/CeO2 for the oxidative carbonylation of phenol was affected by several factors,including the specific surface area,Ce^3+and/or oxygen vacancy content,oxygen species type and Pd(II)content of the catalyst.All these properties were influenced by Zr doping and the calcination temperature of the CZO support.
基金the National Basic Research Program of China (2004CB719500)the Commission of Science and Technology of Shanghai Municipality (06DJ14006)Shanghai Municipal Education Commission (2008CG35)
文摘Cerium-doped MCM-48 molecular sieves were synthesized hydrothermally and characterized by X-ray diffraction, nitrogen adsorption, transmission electron microscope, FT-IR spectroscopy, UV-visible spectroscopy, and Raman spectroscopy. The results showed that all the samples held the structure of MCM-48, and Ce could enter the framework of MCM-48. However, when Ce/Si molar ratio in the sampies was high (0.04 or 0.059), there were CeO2 crystallites as secondary phase in the extraframework of MCM-48. Ce-doped MCM-48 was a very efficient catalyst for the oxidation of cyclohexane in a solvent-free system with oxygen as an oxidant. In the conditions of 0.5 MPa 02 and 413 K for 5 h, the conversion of cyclohexane was 8.1% over Ce-MCM-48-0.02, the total selectivity of cyclohexanol and cyclohaxnone was 98.7%. With an increase of Ce content, the conversion of cyclohexane and the selectivity to cyclohexanol decreased somewhat, but the selectivity to cyclohexanone increased.
文摘Ce-doped titanium oxide nanoparticles were investigated in the paper. The surface structures of undoped and Ce-doped TiO2 nanoparticles were observed by scanning tunneling microscopy (STM). The experimental results of scanning tunneling spectroscopy (STS) show that the surface electronic structures of TiO2 nanoparticles are modified by introducing new electronic states in the surface band gap through cerium ion doping. The results are discussed in terms of the influence of doping concentration on the surface band gap of TiO2.
基金the National Natural Science Foundation of China(No.60778040)the Hi-tech Research and Development Program of China(No.2007AA032400448)+3 种基金the Science and Technology Bureau of Jilin Province(No.20060518)Gifted Youth Program of Jilin Province(No.20060123)the Science and Technology Office of Education of Jilin Province(No.2007162)the Science and Technology Bureau of Key Program for Ministry of Education(No.207025).
文摘ZnO nanorods were synthesized using the sol-gel method, and the effects of annealing temperature and Ce doping on the morphologies and optical properties of ZnO nanostructures were investigated in detail. The XRD measurements showed that the as-synthesized ZnO nanostructures had a hexagonal wurtzite structure. SEM images showed that uniform nanorods formed at 900 °C. Photoluminescence measurements showed an ultraviolet emission peak and a relatively broad visible light emission peak for the samples sintered at different temperatures. The UV emission peak bathochromically shifted when the annealing temperature rose from 850 to 1000 °C. Ce doping decreased the synthesized temperature of the ZnO nanorods to 500 °C, and the UV peaks hypsochromically shifted.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.41373127) and Liaon- ing Provincial Natural Science Foundation of China (No.2013020121).
文摘In order to develop a novel electric light source, the doped high-silica glass was studied on the preparation and spectroscopic properties. ne porous glasses were made firstly and were then immersed in the solution containing Ce ion. Thereafter, the high-silica glasses containing Ce ion were prepared by sintering the porous preform. The spectroscopic properties were studied before and after heath treatment in H-2. The experimental results indicate that the suitable temperature schedules are the most important to prepare doped high-silica glass. The study of the spectra shows that Ce ion can be reduced to low valence state when it is heat-treated in H-2. It can be used to adjust the UV cut-off wavelength of high-silica glass by changing the valence state of Ce ion.
文摘Thispaperisconcerned withthe preparation ofcerium doped yttrium iron garnet which areknown to be an oxide withlarge magneto opticaleffect. Usingtheimproved flux method wesuccessfully grew the bulksinglecrystalsofiron garnet doped by Ce 3 + ions with maximum substitution upto0 349. Here weinvestigatedthedifferentcomposition ofsolution for maxi mum Ce3 + substitution. Thespectra ofthe Faraday rotation andtheoptical absorption were measured inthenearinfrared region fordifferentCe3 + ionsdopediron garnets. The Cesub stitution prominentlyenhancesthe Faradayeffect,andthe Yb and Euionssubstitutefor Yinthe dodecahedralsitesof YIGcanincreasetheconcentration of Ce3 + ions, depresstheforma tion of nonmagnetic Ce4 + ionsbythechargecompensation.