Three-dimensional （3D） hierarchical Pt-Cu tetragonal, highly branched, and dendritic superstructures have been synthesized by a facile template-free hydrothermal approach, showing growth patterns along （111, 110）,...Three-dimensional （3D） hierarchical Pt-Cu tetragonal, highly branched, and dendritic superstructures have been synthesized by a facile template-free hydrothermal approach, showing growth patterns along （111, 110）, （111）, and （100） planes, respectively. These structures have been characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDX）, inductively coupled plasma optical emission spectrometry （ICP-OES） and a detailed formation mechanism has been developed, which shows that the in situ formed 12 and the galvanic replacement reaction between Cu and Pt4, may guide the formation of these superstructures. The comparative electrocatalytic properties have been investigated for methanol and ethanol oxidation. Due to their interconnected arms, sufficient absorption sites, and exposed surfaces, these superstructures exhibit enhanced electrocatalytic performance for electro-oxidation of methanol and ethanol when compared with commercial Pt/C and Pt black.展开更多
This study conducted air particulate matter sampling to measure the total suspended particulate (TSP), PM 10 (particles<10 μmm in aerodynamic diameter) and PM 2 5 (particles<2 5 μmm in aerodynamic diameter) ma...This study conducted air particulate matter sampling to measure the total suspended particulate (TSP), PM 10 (particles<10 μmm in aerodynamic diameter) and PM 2 5 (particles<2 5 μmm in aerodynamic diameter) mass concentration at Tongan district in Xiamen. One hundred and nineteen samples were obtained to measure the mass concentrations of TSP, PM 10 and PM 2 5 during 15 April to 6 June 2002. According to these results, the TSP, PM 10 and PM 2 5 mass concentrations varied from 53 μg·m -3 (from 26 to 105 μg·m -3 ), 48 μg·m -3 (from 23 to 74 μg·m -3 ) and 41 μg·m -3 (from 18 to 62 μg·m -3 ), respectively. 18 elemental concentrations were determined by ICP MS, most elemental profiles were lower than previous studies. However, high levels of Pb and Zn indicate some pollutants existed in air particulate matter.展开更多
Mercury(Hg),arsenic(As) and selenium(Se) are ubiquitous in the environment and exist in a variety of species,which have great influence on their transport,bioaccumulation and toxicity.This review presents the recent r...Mercury(Hg),arsenic(As) and selenium(Se) are ubiquitous in the environment and exist in a variety of species,which have great influence on their transport,bioaccumulation and toxicity.This review presents the recent research progress in speciation analysis of Hg,As,and Se,with emphasis on enhanced cold vapor generation as interface for liquid chromatography and atomic spectrometry,speciation of volatile species in gas phase,and isotope dilution technique to improve the precision and accuracy of speciation.Hyphenated techniques to characterize the complexes of Hg and As with phytochelatins and chromatographic separation coupled with multi-collector-inductively coupled plasma mass spectrometry to measure species-specific isotopic ratios,are also briefly discussed.展开更多
基金This work was supported by the National Natural Science Foundation of China （Nos. 91127040 and 21221062）, and the State Key Project of Fundamental Research for Nanoscience and Nanotechnology （No. 2011CB932402）.
文摘Three-dimensional （3D） hierarchical Pt-Cu tetragonal, highly branched, and dendritic superstructures have been synthesized by a facile template-free hydrothermal approach, showing growth patterns along （111, 110）, （111）, and （100） planes, respectively. These structures have been characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDX）, inductively coupled plasma optical emission spectrometry （ICP-OES） and a detailed formation mechanism has been developed, which shows that the in situ formed 12 and the galvanic replacement reaction between Cu and Pt4, may guide the formation of these superstructures. The comparative electrocatalytic properties have been investigated for methanol and ethanol oxidation. Due to their interconnected arms, sufficient absorption sites, and exposed surfaces, these superstructures exhibit enhanced electrocatalytic performance for electro-oxidation of methanol and ethanol when compared with commercial Pt/C and Pt black.
文摘This study conducted air particulate matter sampling to measure the total suspended particulate (TSP), PM 10 (particles<10 μmm in aerodynamic diameter) and PM 2 5 (particles<2 5 μmm in aerodynamic diameter) mass concentration at Tongan district in Xiamen. One hundred and nineteen samples were obtained to measure the mass concentrations of TSP, PM 10 and PM 2 5 during 15 April to 6 June 2002. According to these results, the TSP, PM 10 and PM 2 5 mass concentrations varied from 53 μg·m -3 (from 26 to 105 μg·m -3 ), 48 μg·m -3 (from 23 to 74 μg·m -3 ) and 41 μg·m -3 (from 18 to 62 μg·m -3 ), respectively. 18 elemental concentrations were determined by ICP MS, most elemental profiles were lower than previous studies. However, high levels of Pb and Zn indicate some pollutants existed in air particulate matter.
基金supported by the National Natural Science Foundation of China (20877082,21120102040,21025729)
文摘Mercury(Hg),arsenic(As) and selenium(Se) are ubiquitous in the environment and exist in a variety of species,which have great influence on their transport,bioaccumulation and toxicity.This review presents the recent research progress in speciation analysis of Hg,As,and Se,with emphasis on enhanced cold vapor generation as interface for liquid chromatography and atomic spectrometry,speciation of volatile species in gas phase,and isotope dilution technique to improve the precision and accuracy of speciation.Hyphenated techniques to characterize the complexes of Hg and As with phytochelatins and chromatographic separation coupled with multi-collector-inductively coupled plasma mass spectrometry to measure species-specific isotopic ratios,are also briefly discussed.
