Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appro...Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.展开更多
In order to investigate the suitability of ternary rare earth sulfide LanCe2 xS3 in plastic application as a red pigment, we prepared LaxCe2 xS3 via the sulfurization of the oxide powders using CS2 gas. In the sulfuri...In order to investigate the suitability of ternary rare earth sulfide LanCe2 xS3 in plastic application as a red pigment, we prepared LaxCe2 xS3 via the sulfurization of the oxide powders using CS2 gas. In the sulfurization of LaxCe2_xS3, β-phase and y-phase ter- nary rare earth sulfide LaxCe2_xS3 were synthesized at the sulfufization temperature of 1000 and 1250 ℃ for 3 h, respectively. The UV-vis absorption spectra of synthesized LaxCe2_xS3 showed that the absorption wavelengths of 13-phase and y-phase LaxCe2_xS3 samies were in the region of 617-70 nm and 607-53 nm, respectively. They were in red absorption region. Furthermore, the scanning electron microscopy （SEM） results of the synthesized LaxCe2-S3 samples were investigated. The typical SEM microgmphs indicated that the particle sizes of synthesized LaxCe2 xS3 were in the range of 0.5-5 μm.展开更多
Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of...Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.展开更多
基金supported by the National Natural Science Foundation of China (20501023)the Natural Science Foundation of Guangdong for Doctorial Training Base (5300527)
文摘Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.
基金Project supported by National Natural Science Foundation of China (20501023)Natural Science Foundation of Henan Province (2010A430010)Scientific and Technical Foundation of China National Coal Association (MTKJ2010-357)
文摘In order to investigate the suitability of ternary rare earth sulfide LanCe2 xS3 in plastic application as a red pigment, we prepared LaxCe2 xS3 via the sulfurization of the oxide powders using CS2 gas. In the sulfurization of LaxCe2_xS3, β-phase and y-phase ter- nary rare earth sulfide LaxCe2_xS3 were synthesized at the sulfufization temperature of 1000 and 1250 ℃ for 3 h, respectively. The UV-vis absorption spectra of synthesized LaxCe2_xS3 showed that the absorption wavelengths of 13-phase and y-phase LaxCe2_xS3 samies were in the region of 617-70 nm and 607-53 nm, respectively. They were in red absorption region. Furthermore, the scanning electron microscopy （SEM） results of the synthesized LaxCe2-S3 samples were investigated. The typical SEM microgmphs indicated that the particle sizes of synthesized LaxCe2 xS3 were in the range of 0.5-5 μm.
基金supported by New Century Educational Talents Plan of Chinese Education Ministry, China (NCET-10-0171)the National Natural Sci-ence Foundation of China (60979003)the Fundamental Research Funds for the Central Universities (2009QN123)
文摘Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.
