The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The val...The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The valence-band photoelectron spectroscopy results demonstrate that the Ti^3＋3d feature attenuates quickly with the initial deposition of Au clusters, implying that Au clusters nucleate at the oxygen vacancy sites. The Au4f core-level photoelectron spectroscopy results directly prove the existence of charge transfer from oxygen vacancies to Au clusters. The thermal stability of Au clusters on the partially-reduced and stoichiometric TiO2（110） surfaces was also comparatively investigated by the annealing experiments. With the same film thickness, Au clusters are more thermally stable on the partially-reduced TiO2（110） surface than on the stoichiometric TiO2（110） surface. Meanwhile, large Au nanoparticles are more thermally stable than fine Au nanoparticles.展开更多
Due to the low absorption contrast of plant tissues, traditional x-ray radiography has not been included in the microscopic techniques used in the identification of traditional Chinese medicines （TCMs）. With the dev...Due to the low absorption contrast of plant tissues, traditional x-ray radiography has not been included in the microscopic techniques used in the identification of traditional Chinese medicines （TCMs）. With the development of x-ray phase contrast imaging （XPCI） in recent years, weakly absorbing materials could also be imaged by x- rays. Here we investigate microstructures of TCMs utilizing XPCI based on a nano-focus x-ray tube. The results demonstrated that XPCI is capable of revealing the microstructures of TCMs used as judging criteria in the identification of TCMs. The major advantages of the new method are nondestructivity, no special demand for sample preparation and suitability for thick samples.展开更多
Inorganic-organic hybrid WOx-ethylenediamine （WO/-EDA） nanowires have been produced by a simple, low-cost and high-yield solvothermal method. These WO/-EDA hybrid nanowires have unique lamellar mesostructures with a...Inorganic-organic hybrid WOx-ethylenediamine （WO/-EDA） nanowires have been produced by a simple, low-cost and high-yield solvothermal method. These WO/-EDA hybrid nanowires have unique lamellar mesostructures with an alternate stacking of an interconnected [WO6] octahedral layer and a monolayer of ethylenediamine molecules. This hybrid structure integrated the functionality of ethylenediamine with the stability of the WOx frameworks. In situ synchrotron- radiation X-ray diffraction is used to elucidate a possible formation mechanism of the hybrid WOx-EDA. The nanowire morphology, lamellar structure and abundant functional amino groups endow them with versatile abilities. For example, in heavy metal ion adsorption the WOx-EDA nanowires display exceptional adsorption capabilities of 925 mg·g^-1 for Pb^2＋ and 610 mg·g^-1 for UO2^2＋. The nanowires also show outstanding stability and activity as a heterogeneous base catalyst in the Knoevenagel condensation reaction at room temperature. The catalyst can be recycled and reused for 20 cycles with nearly 100% yields. This study provides a new strategy to design inorganic-organic hybrid materials, and offers a multifunctional material that is a highly efficient adsorbent and sustainable catalyst.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20773113 and No.20803072）, the Hundred Talent Program of Chinese Academy of Sciences, the MOE Program for Changjiang Scholars and Innovative Research Team （No.IRT0756）, and the MPG-CAS Partner-group Program.
文摘The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The valence-band photoelectron spectroscopy results demonstrate that the Ti^3＋3d feature attenuates quickly with the initial deposition of Au clusters, implying that Au clusters nucleate at the oxygen vacancy sites. The Au4f core-level photoelectron spectroscopy results directly prove the existence of charge transfer from oxygen vacancies to Au clusters. The thermal stability of Au clusters on the partially-reduced and stoichiometric TiO2（110） surfaces was also comparatively investigated by the annealing experiments. With the same film thickness, Au clusters are more thermally stable on the partially-reduced TiO2（110） surface than on the stoichiometric TiO2（110） surface. Meanwhile, large Au nanoparticles are more thermally stable than fine Au nanoparticles.
文摘Due to the low absorption contrast of plant tissues, traditional x-ray radiography has not been included in the microscopic techniques used in the identification of traditional Chinese medicines （TCMs）. With the development of x-ray phase contrast imaging （XPCI） in recent years, weakly absorbing materials could also be imaged by x- rays. Here we investigate microstructures of TCMs utilizing XPCI based on a nano-focus x-ray tube. The results demonstrated that XPCI is capable of revealing the microstructures of TCMs used as judging criteria in the identification of TCMs. The major advantages of the new method are nondestructivity, no special demand for sample preparation and suitability for thick samples.
基金Acknowledgements We are grateful for financial support from the National Basic Research Program of China （2009CB930400）, the National Natural Science Foundation of China （NSFC 21121063） and the Joint Research Project funding （GJHZ1224） from the Chinese Academy of Sciences and the Commonwealth Scientific and Industrial Research Organisation （CSIRO）. We thank the Institute of Modem Physics, Chinese Academy of Sciences for providing the UO2（NO3）2＂6H20 salts and uranium content measurements. We acknowledge the Australian Synchrotron for access to the Powder Diffraction beamline. We thank Ian Madsen （CSIRO Process Science and Engineering） for providing access to the in situ XRD instrument and for a critical reading of the manuscript. The CSIRO Office of the Chief Executive （OCE） Postdoctoral and Science Leader Schemes are acknowledged for supporting this work. R. A. C. acknowledges the Australian Research Council for a Future Fellowship （FT0990583）.
文摘Inorganic-organic hybrid WOx-ethylenediamine （WO/-EDA） nanowires have been produced by a simple, low-cost and high-yield solvothermal method. These WO/-EDA hybrid nanowires have unique lamellar mesostructures with an alternate stacking of an interconnected [WO6] octahedral layer and a monolayer of ethylenediamine molecules. This hybrid structure integrated the functionality of ethylenediamine with the stability of the WOx frameworks. In situ synchrotron- radiation X-ray diffraction is used to elucidate a possible formation mechanism of the hybrid WOx-EDA. The nanowire morphology, lamellar structure and abundant functional amino groups endow them with versatile abilities. For example, in heavy metal ion adsorption the WOx-EDA nanowires display exceptional adsorption capabilities of 925 mg·g^-1 for Pb^2＋ and 610 mg·g^-1 for UO2^2＋. The nanowires also show outstanding stability and activity as a heterogeneous base catalyst in the Knoevenagel condensation reaction at room temperature. The catalyst can be recycled and reused for 20 cycles with nearly 100% yields. This study provides a new strategy to design inorganic-organic hybrid materials, and offers a multifunctional material that is a highly efficient adsorbent and sustainable catalyst.
