Nanocrystalline Na2ZrO3 was demonstrated as a promising acceptor for CO2 capture at elevated temperatures. The mechanism of nanocrystalline Na2ZrO3 formation from the soft-chemistry route is elucidated by varying prec...Nanocrystalline Na2ZrO3 was demonstrated as a promising acceptor for CO2 capture at elevated temperatures. The mechanism of nanocrystalline Na2ZrO3 formation from the soft-chemistry route is elucidated by varying precursors, preparation methods, and calciantion temperatures, combining detailed characterizations by X-ray diffraction （XRD） and scanning electron microscope （SEM） at different steps in the process. The results revealed that the drying method such as spraying drying and simple evaporation-drying did not influence the final product prop- erties. However both Na and Zr precursors had remarkable influences on the Na2ZrO3 formation. The solid reaction of Na intermediate and nanocrystalline ZrO2 in the calcination was identified as the key step for the Na2ZrO3 formation, where the formation of molten phase Na intermediate was found to be crucial to facilitate the solid reaction. We provided principles for rational design of the chemistry for the Na2ZrO3 formation where the formation of Na intermediate with low melting points is essential. Pure nanocrystalline Na2ZrO3 can be synthesized from a mixture containing sodium nitrate and zirconoxy citrate via the formation of NaNO3 with low melting point. However, it is not possible to form pure nanocrystalline Na2ZrO3 at relatively low temperatures from the mixtures of NaAc/ZrO（NO3）2 or NaCA/ZrOC12 due to the formation of Na2CO3 and NaC1 with high melting points.展开更多
Ultrafine Gd2O3：Eu3＋nanocrystals were successfully prepared by a simple reverse microemulsion method and subsequent calcination. Their structural, optical and magnetic properties were investigated using scanning ele...Ultrafine Gd2O3：Eu3＋nanocrystals were successfully prepared by a simple reverse microemulsion method and subsequent calcination. Their structural, optical and magnetic properties were investigated using scanning electron microscopy （SEM）, transmis-sion electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier transform infrared （FTIR）, photoluminescence （PL）, and magnetic property measurement system （MPMS）. The amorphous Gd2（CO3）3：Eu3＋colloidal spheres were proved as an intermediate product, and gradually transformed into crystallized Gd2O3：Eu3＋with average diameter less than 100 nm. The paramagnetic property of the synthesized Gd2O3：Eu3＋nanocrystals were confirmed with its linear hysteresis plot （M-H）. And Gd2O3：Eu3＋nanocrystals showed high contrast T1-enhancing modality due to the presence of the Gd3＋ ions onto the particle surface. In addition, the application of the Gd2O3：Eu3＋nanocrystals as biotag for cell labeling was reported, red fluorescence from Eu3＋ions observed by fluorescence micros-copy showed that the nanocrystals could permeate the cell membrane. Cytotoxicity studies of the Gd2O3：Eu3＋nanocrystals showed no adverse effect on cell viability, evidencing their high biological compatibility. Therefore, the nanoprobe formed from Gd2O3：Eu3＋nanocrystals provided the dual modality of optical and magnetic resonance imaging.展开更多
Y（OH）3：Eu3＋ nanotubes were synthesized using a facile hydrothermal method, and then, Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing. The resulting Pt...Y（OH）3：Eu3＋ nanotubes were synthesized using a facile hydrothermal method, and then, Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing. The resulting Pt/Y2O3：Eu3＋ composite nanotubes not only exhibited enhanced red luminescence under 255- or 468-nm excitation but could also be used to improve the efficiency of dye- sensitized solar cells, resulting in an efficiency of 8.33%, which represents a significant enhancement of 11.96% compared with a solar cell without the com- posite nanotubes. Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dyel I3/I- electrolyte interface of the TiO2-Pt/Y203：Eu3~ composite cell was much smaller than that of a pure TiO2 cell. In addition, the TiO2-Pt/Y2O3：Eu3＋ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.展开更多
In this paper, the Gd2O3：Eu3＋,Tb3＋phosphors with different doping concentrations of Eu3＋and Tb3＋ions were prepared by a hydrothermal method for nanocrystals and the solid-phase method for microcrystals. The inter...In this paper, the Gd2O3：Eu3＋,Tb3＋phosphors with different doping concentrations of Eu3＋and Tb3＋ions were prepared by a hydrothermal method for nanocrystals and the solid-phase method for microcrystals. The interaction of the doped ions with different concentrations and the luminescent properties of the nanocrystals and microcrystals were studied systematically. Their structure and morphology of Gd2O3：Eu3＋,Tb3＋phosphors were analyzed by means of X-ray powder diffraction （XRD）, transmission electron mi-croscopy （TEM） and scanning electron microscopy （SEM）. The photoluminescence （PL） properties of Gd2O3：Eu3＋,Tb3＋phosphors were also systematically investigated. The results indicated that when the concentration of doped Eu3＋was fixed at 1 mol.%, the emis-sion intensity of Eu3＋ions was degenerating with Tb3＋content increasing, while when the Tb3＋content was fixed at 1 mol.%, the emission intensity of Tb3＋ions reached a maximum when the concentration of Eu3＋was 2 mol.%, implying that the energy transfer from Eu3＋to Tb3＋took place. In addition, Tb3＋could inspire blue-green light and the Eu3＋could inspire red light. Therefore co-doping systems by controlling the doping concentration and the hosts are the potential white emission materials.展开更多
文摘Nanocrystalline Na2ZrO3 was demonstrated as a promising acceptor for CO2 capture at elevated temperatures. The mechanism of nanocrystalline Na2ZrO3 formation from the soft-chemistry route is elucidated by varying precursors, preparation methods, and calciantion temperatures, combining detailed characterizations by X-ray diffraction （XRD） and scanning electron microscope （SEM） at different steps in the process. The results revealed that the drying method such as spraying drying and simple evaporation-drying did not influence the final product prop- erties. However both Na and Zr precursors had remarkable influences on the Na2ZrO3 formation. The solid reaction of Na intermediate and nanocrystalline ZrO2 in the calcination was identified as the key step for the Na2ZrO3 formation, where the formation of molten phase Na intermediate was found to be crucial to facilitate the solid reaction. We provided principles for rational design of the chemistry for the Na2ZrO3 formation where the formation of Na intermediate with low melting points is essential. Pure nanocrystalline Na2ZrO3 can be synthesized from a mixture containing sodium nitrate and zirconoxy citrate via the formation of NaNO3 with low melting point. However, it is not possible to form pure nanocrystalline Na2ZrO3 at relatively low temperatures from the mixtures of NaAc/ZrO（NO3）2 or NaCA/ZrOC12 due to the formation of Na2CO3 and NaC1 with high melting points.
基金Project supported by Education Department of Jiangxi Province(GJJ14578,GJJ13216)
文摘Ultrafine Gd2O3：Eu3＋nanocrystals were successfully prepared by a simple reverse microemulsion method and subsequent calcination. Their structural, optical and magnetic properties were investigated using scanning electron microscopy （SEM）, transmis-sion electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier transform infrared （FTIR）, photoluminescence （PL）, and magnetic property measurement system （MPMS）. The amorphous Gd2（CO3）3：Eu3＋colloidal spheres were proved as an intermediate product, and gradually transformed into crystallized Gd2O3：Eu3＋with average diameter less than 100 nm. The paramagnetic property of the synthesized Gd2O3：Eu3＋nanocrystals were confirmed with its linear hysteresis plot （M-H）. And Gd2O3：Eu3＋nanocrystals showed high contrast T1-enhancing modality due to the presence of the Gd3＋ ions onto the particle surface. In addition, the application of the Gd2O3：Eu3＋nanocrystals as biotag for cell labeling was reported, red fluorescence from Eu3＋ions observed by fluorescence micros-copy showed that the nanocrystals could permeate the cell membrane. Cytotoxicity studies of the Gd2O3：Eu3＋nanocrystals showed no adverse effect on cell viability, evidencing their high biological compatibility. Therefore, the nanoprobe formed from Gd2O3：Eu3＋nanocrystals provided the dual modality of optical and magnetic resonance imaging.
基金This work was supported by the National Natural Science Foundation of China （No. 21471050） and Heilongjiang Province Natural Science Foundation of Key Projects （No. ZD201301）.
文摘Y（OH）3：Eu3＋ nanotubes were synthesized using a facile hydrothermal method, and then, Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing. The resulting Pt/Y2O3：Eu3＋ composite nanotubes not only exhibited enhanced red luminescence under 255- or 468-nm excitation but could also be used to improve the efficiency of dye- sensitized solar cells, resulting in an efficiency of 8.33%, which represents a significant enhancement of 11.96% compared with a solar cell without the com- posite nanotubes. Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dyel I3/I- electrolyte interface of the TiO2-Pt/Y203：Eu3~ composite cell was much smaller than that of a pure TiO2 cell. In addition, the TiO2-Pt/Y2O3：Eu3＋ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.
基金supported by Natural Science Foundation of Jiangxi Province(20132BAB206008)
文摘In this paper, the Gd2O3：Eu3＋,Tb3＋phosphors with different doping concentrations of Eu3＋and Tb3＋ions were prepared by a hydrothermal method for nanocrystals and the solid-phase method for microcrystals. The interaction of the doped ions with different concentrations and the luminescent properties of the nanocrystals and microcrystals were studied systematically. Their structure and morphology of Gd2O3：Eu3＋,Tb3＋phosphors were analyzed by means of X-ray powder diffraction （XRD）, transmission electron mi-croscopy （TEM） and scanning electron microscopy （SEM）. The photoluminescence （PL） properties of Gd2O3：Eu3＋,Tb3＋phosphors were also systematically investigated. The results indicated that when the concentration of doped Eu3＋was fixed at 1 mol.%, the emis-sion intensity of Eu3＋ions was degenerating with Tb3＋content increasing, while when the Tb3＋content was fixed at 1 mol.%, the emission intensity of Tb3＋ions reached a maximum when the concentration of Eu3＋was 2 mol.%, implying that the energy transfer from Eu3＋to Tb3＋took place. In addition, Tb3＋could inspire blue-green light and the Eu3＋could inspire red light. Therefore co-doping systems by controlling the doping concentration and the hosts are the potential white emission materials.
