The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid soluti...The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid solution. The ground states of Fe-Y com-pounds and the thermodynamic properties of bcc Fe were calculated, and the stable and metastable structures of Fe-Y compounds were predicted as well. With the temperature increasing, the Y activity coefficient in bcc Fe matrix increased rapidly, and the interac-tion between Y and Fe became more favorable. Based on the calculated thermodynamic properties, the solubility of Y in bcc Fe ma-trix as a function of temperature was predicted, and compared with the experimental data.展开更多
A novel Fe-Y composite oxide(Fe:Y-6.5) nanocluster was synthesized by self-assembly approach.The α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline with diameter around 10 nm are homogeneously assembled to form a clu...A novel Fe-Y composite oxide(Fe:Y-6.5) nanocluster was synthesized by self-assembly approach.The α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline with diameter around 10 nm are homogeneously assembled to form a cluster architecture which are constituted of Fe6.5Y composite oxide particles.Additional oxygen vacancies are introduced with cubic-Y_(2)O_(3),and the oxygen vacancies as Fe^(3+)-V_(0)-Y^(3+) between α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline are generated by self-assembly process.Magnetic hysteresis loops recorded by vibrating sample magnetometry at 273 K display a ferromagnetic order,related to the fact that Fe^(3+)-V_(o)-Y^(3+) act as defect centers in the bound magnetic polaron model for Fe-Y composite oxide nanomaterial.The ferromagnetic prope rties are proportional to oxygen vacancy co ntents,and maximum magnetization(M_(m)) value of the nano-cluster reaches 5.14 A·m^(2)/g.展开更多
A series of Fe-Y zeolite catalysts with different Fe loading were prepared by ferrocene sublimation under solvent and wa- ter-free conditions. The dispersion, structure and morphology of the iron species on the Fe-Y c...A series of Fe-Y zeolite catalysts with different Fe loading were prepared by ferrocene sublimation under solvent and wa- ter-free conditions. The dispersion, structure and morphology of the iron species on the Fe-Y catalysts were characterized by XRD, TEM and UV-Vis. The catalytic activities of Fe-Y samples were measured in selective catalytic redaction of NO with ammonia （NH3-SCR）. The results showed that the iron species on the HY zeolite support were mainly made up of isolated Fe3＋ ions, FexOy oligomers and a little amount of 〈 3 nm spherical Fe203 particles. Isolated Fe3＋ ions are predominating among all the Fe-Y catalysts. The sum of isolated Fe3＋ ions and FexOy oligomers took up more than 90% percent of total iron species on the Fe-Y till 10.0 wt% loading of Fe.展开更多
基金supported by the National Natural Science Foundation of China(51101083)
文摘The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid solution. The ground states of Fe-Y com-pounds and the thermodynamic properties of bcc Fe were calculated, and the stable and metastable structures of Fe-Y compounds were predicted as well. With the temperature increasing, the Y activity coefficient in bcc Fe matrix increased rapidly, and the interac-tion between Y and Fe became more favorable. Based on the calculated thermodynamic properties, the solubility of Y in bcc Fe ma-trix as a function of temperature was predicted, and compared with the experimental data.
基金Project supported by National Key R&D Program of China(2017YFB0305801)the Joint Funds of NSFC-Liaoning(U1508213)。
文摘A novel Fe-Y composite oxide(Fe:Y-6.5) nanocluster was synthesized by self-assembly approach.The α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline with diameter around 10 nm are homogeneously assembled to form a cluster architecture which are constituted of Fe6.5Y composite oxide particles.Additional oxygen vacancies are introduced with cubic-Y_(2)O_(3),and the oxygen vacancies as Fe^(3+)-V_(0)-Y^(3+) between α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline are generated by self-assembly process.Magnetic hysteresis loops recorded by vibrating sample magnetometry at 273 K display a ferromagnetic order,related to the fact that Fe^(3+)-V_(o)-Y^(3+) act as defect centers in the bound magnetic polaron model for Fe-Y composite oxide nanomaterial.The ferromagnetic prope rties are proportional to oxygen vacancy co ntents,and maximum magnetization(M_(m)) value of the nano-cluster reaches 5.14 A·m^(2)/g.
基金support of the National Natural Science Foundation of China(20903080)
文摘A series of Fe-Y zeolite catalysts with different Fe loading were prepared by ferrocene sublimation under solvent and wa- ter-free conditions. The dispersion, structure and morphology of the iron species on the Fe-Y catalysts were characterized by XRD, TEM and UV-Vis. The catalytic activities of Fe-Y samples were measured in selective catalytic redaction of NO with ammonia （NH3-SCR）. The results showed that the iron species on the HY zeolite support were mainly made up of isolated Fe3＋ ions, FexOy oligomers and a little amount of 〈 3 nm spherical Fe203 particles. Isolated Fe3＋ ions are predominating among all the Fe-Y catalysts. The sum of isolated Fe3＋ ions and FexOy oligomers took up more than 90% percent of total iron species on the Fe-Y till 10.0 wt% loading of Fe.
