Nominal composition of Ca1-xZnxTiO3 ： 0. 002Pr^3 ＋ （x = 0. 000 - 0. 200） phosphors were prepared by conventional solid reaction route. XRD and PL measurements were used to investigate the solid-solution structure ...Nominal composition of Ca1-xZnxTiO3 ： 0. 002Pr^3 ＋ （x = 0. 000 - 0. 200） phosphors were prepared by conventional solid reaction route. XRD and PL measurements were used to investigate the solid-solution structure and luminescence properties of Zn-doped Ca1-xZnxTiO3：0.002Pr^3＋ phosphors. The effect of solid-solution structure formed by substitution between Ca^2 ＋ and Zn^2＋ ions on the luminescent properties was analyzed. The results reveal that, with the increase of Zn substitution content below 0.010, lattice parameters and the intensity of excitation peak at both 260 and 330 nm as well as the corresponding 610 nm emission intensity are monotonously decreased quickly in a similar tendency. Also, the evolution of luminescence intensity and crystal cell parameters against Zn doping concentration are in good agreement. Above results are closely related with the structure change within Ca1- xZnxTiO3：0.002Pr^3＋ solid-solution phase formed by the Zn ions substitution for the Ca sites. Present study reveals that the solid-solution structure formed by substitution between Ca^2＋ and Zn^2＋ ions has significant effect on the luminescence properties of single phase Ca1-xZnxTiO3：0.002Pr^3＋ phosphors.展开更多
The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 ...The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.展开更多
In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 a...In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 at%Eu,x at%Pr(x=0,0.2,0.5,1,2 and 5)and(Lu1-yScy)_(2)O_(3):5 at%Eu(y=0,20 at%,50 at%and 70 at%)single crystals were grown by floating zone(FZ)method in air atmosphere.The structures of as-grown crystals were determined by X-ray diffraction(XRD).The scintillation,photoluminescence properties and carrier trap states were investigated through afterglow,X-ray excitation luminescence(XEL),transmittance,photoluminescence excitation(PLE)and photoluminescence(PL),PL decay and thermal stimulated luminescence(TSL)curves.It is found that with the increase of Pr^(3+)concentration,the afterglow level of the system decreases at the expense of scintillation luminescence efficiency.Meanwhile,although Sc_(2)O_(3):Eu presents much lower afterglow intensity than Lu_(2)O_(3):Eu,the addition of Sc_(2)O_(3)will just increase the afterglow level of the(Lu1-yScy)_(2)O_(3):5 at%Eu single crystal system.Possible mechanisms for above phenomena are discussed based on experimental results.展开更多
Artificial Z-scheme photocatalytic systems have received considerable attention in recent years because they can achieve wide light-absorption, high charge-separation efficiency, and strong redox ability simultaneousl...Artificial Z-scheme photocatalytic systems have received considerable attention in recent years because they can achieve wide light-absorption, high charge-separation efficiency, and strong redox ability simultaneously. Nevertheless, it is still challenging to exploit low-cost and stable Zscheme photocatalysts with highly-efficient H2 evolution from solar water-splitting so far. Herein, we report a novel all-solidstate Z-scheme photocatalyst Cd1-xZnxS@WO3-x consisting of Cd1-xZnxS nanorods coated with oxygen-deficient WO3-x amorphous layers. The Cd1-xZnxS@WO3-x exhibits an outstanding H2 evolution reaction(HER) activity as compared with Pt-loaded Cd1-xZnxS and most WO3- and Cd S-based photocatalysts, due to the generation of stronger reducing electrons through the appropriate Zn-doping in Cd1-xZnxS and the enhanced charge transfer by introducing oxygen vacancies(W^5+/OVs) into the ultrathin WO3-x amorphous coatings. The optimal HER rate of Cd1-xZnxS@WO3- xis determined to be 21.68 mmol h^-1 g^-1, which is further raised up to 28.25 mmol h^-1 g^-1(about 12 times more than that of Pt/Cd1-xZnxS) when Cd1-xZnxS@WO3-x is hybridized by Co Ox and Ni Oxdual cocatalysts(Cd1-xZnxS@WO3-x/CoOx/NiOx)through in-situ photo-deposition. Moreover, the corresponding apparent quantum yield(AQY) at 420 nm is significantly increased from 34.6% for Cd1-xZnxS@WO3-x to 60.8% for Cd1-xZnxS@WO3-x/CoOx/NiOx. In addition, both Cd1-xZnxS@WO3-x and Cd1-xZnxS@WO3-x/CoOx/NiOx demonstrate good stability towards HER. The results displayed in this work will inspire the rational design and synthesis of high-performance nanostructures for photocatalytic applications.展开更多
文摘Nominal composition of Ca1-xZnxTiO3 ： 0. 002Pr^3 ＋ （x = 0. 000 - 0. 200） phosphors were prepared by conventional solid reaction route. XRD and PL measurements were used to investigate the solid-solution structure and luminescence properties of Zn-doped Ca1-xZnxTiO3：0.002Pr^3＋ phosphors. The effect of solid-solution structure formed by substitution between Ca^2 ＋ and Zn^2＋ ions on the luminescent properties was analyzed. The results reveal that, with the increase of Zn substitution content below 0.010, lattice parameters and the intensity of excitation peak at both 260 and 330 nm as well as the corresponding 610 nm emission intensity are monotonously decreased quickly in a similar tendency. Also, the evolution of luminescence intensity and crystal cell parameters against Zn doping concentration are in good agreement. Above results are closely related with the structure change within Ca1- xZnxTiO3：0.002Pr^3＋ solid-solution phase formed by the Zn ions substitution for the Ca sites. Present study reveals that the solid-solution structure formed by substitution between Ca^2＋ and Zn^2＋ ions has significant effect on the luminescence properties of single phase Ca1-xZnxTiO3：0.002Pr^3＋ phosphors.
基金This work was supported by the National Naturel Science Foundation of China(No.600740i9).
文摘The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.
基金supported by National Natural Science Foundation of China(12175130,11875187)the Opening Project of State Key Laboratory of Key Laboratory of Transparent Opto-functional Inorganic Materials,Chinese Academy of Sciences(KLTOIM202002)。
文摘In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 at%Eu,x at%Pr(x=0,0.2,0.5,1,2 and 5)and(Lu1-yScy)_(2)O_(3):5 at%Eu(y=0,20 at%,50 at%and 70 at%)single crystals were grown by floating zone(FZ)method in air atmosphere.The structures of as-grown crystals were determined by X-ray diffraction(XRD).The scintillation,photoluminescence properties and carrier trap states were investigated through afterglow,X-ray excitation luminescence(XEL),transmittance,photoluminescence excitation(PLE)and photoluminescence(PL),PL decay and thermal stimulated luminescence(TSL)curves.It is found that with the increase of Pr^(3+)concentration,the afterglow level of the system decreases at the expense of scintillation luminescence efficiency.Meanwhile,although Sc_(2)O_(3):Eu presents much lower afterglow intensity than Lu_(2)O_(3):Eu,the addition of Sc_(2)O_(3)will just increase the afterglow level of the(Lu1-yScy)_(2)O_(3):5 at%Eu single crystal system.Possible mechanisms for above phenomena are discussed based on experimental results.
基金financially supported by the National Natural Science Foundation of China (51572136, 51772162, 21571112, 51802170 and 21801150)the Natural Science Foundation of Shandong Province (ZR2018BEM014, ZR2018LB008 andZR2019MB001)+2 种基金Taishan Scholar Foundation of Shandong Province (H. W., ts201712047)the Special Fund Project to Guide Development of Local Science and Technology by Central Government (H.W.)Taishan Scholar Program of Advantage and Characteristic Discipline Team of Eco Chemical Process and Technology
文摘Artificial Z-scheme photocatalytic systems have received considerable attention in recent years because they can achieve wide light-absorption, high charge-separation efficiency, and strong redox ability simultaneously. Nevertheless, it is still challenging to exploit low-cost and stable Zscheme photocatalysts with highly-efficient H2 evolution from solar water-splitting so far. Herein, we report a novel all-solidstate Z-scheme photocatalyst Cd1-xZnxS@WO3-x consisting of Cd1-xZnxS nanorods coated with oxygen-deficient WO3-x amorphous layers. The Cd1-xZnxS@WO3-x exhibits an outstanding H2 evolution reaction(HER) activity as compared with Pt-loaded Cd1-xZnxS and most WO3- and Cd S-based photocatalysts, due to the generation of stronger reducing electrons through the appropriate Zn-doping in Cd1-xZnxS and the enhanced charge transfer by introducing oxygen vacancies(W^5+/OVs) into the ultrathin WO3-x amorphous coatings. The optimal HER rate of Cd1-xZnxS@WO3- xis determined to be 21.68 mmol h^-1 g^-1, which is further raised up to 28.25 mmol h^-1 g^-1(about 12 times more than that of Pt/Cd1-xZnxS) when Cd1-xZnxS@WO3-x is hybridized by Co Ox and Ni Oxdual cocatalysts(Cd1-xZnxS@WO3-x/CoOx/NiOx)through in-situ photo-deposition. Moreover, the corresponding apparent quantum yield(AQY) at 420 nm is significantly increased from 34.6% for Cd1-xZnxS@WO3-x to 60.8% for Cd1-xZnxS@WO3-x/CoOx/NiOx. In addition, both Cd1-xZnxS@WO3-x and Cd1-xZnxS@WO3-x/CoOx/NiOx demonstrate good stability towards HER. The results displayed in this work will inspire the rational design and synthesis of high-performance nanostructures for photocatalytic applications.
