Wurtzite ZnO microspheres, 5.5-11 μm in diameter and with smooth surfaces, were prepared in absolute ethanol via a simple template-free method in the presence of ethylenediamine. The products were characterized using...Wurtzite ZnO microspheres, 5.5-11 μm in diameter and with smooth surfaces, were prepared in absolute ethanol via a simple template-free method in the presence of ethylenediamine. The products were characterized using X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. This simple method to fabricate ZnO microspheres shows high yield （〉90%） and good reproducibiliry. The formation process of ZnO microspheres was discussed. The as-obtained ZnO microspheres are expected to provide some immediate advantages for optical, microelectronic, and biological applications.展开更多
Single phase and well-crystallined todorokite were synthesized by heating and re-fluxing process from birnessite as a precursor. The average chemical composition of the synthe-sized todorokites by refluxing for 8 h an...Single phase and well-crystallined todorokite were synthesized by heating and re-fluxing process from birnessite as a precursor. The average chemical composition of the synthe-sized todorokites by refluxing for 8 h and for 24 h was Mg0.19MnO2.11(H2O)1.15 and Mg0.17- MnO2.10(H2O)0.88, respectively. The crystallinity of the todorokite increased and no other phase was produced with increasing refluxing period. The synthesized todorokites have the same morphologies and the similar structural characteristics with the natural todorokites and hydro-thermally synthesized samples. The chemical compositions of the synthetic tordorokites by re-fluxing process are close to those of todorokites synthesized by hydrothermal process, except a higher average oxidation state of Mn for the former.展开更多
Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are ana...Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.展开更多
基金supported by the National High TechnologyResearch and Development Program of China (2006AA03Z358)the National Natural Science Foundation of China (20236020)+2 种基金the Shanghai Rising-Star Program (06QA14013)the Special Projectsfor Key Laboratories in Shanghai (05DZ22302, 06DZ22008)the Special Projects for Nanotechnology of Shanghai (0552nm001,0652nm034)
文摘Wurtzite ZnO microspheres, 5.5-11 μm in diameter and with smooth surfaces, were prepared in absolute ethanol via a simple template-free method in the presence of ethylenediamine. The products were characterized using X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. This simple method to fabricate ZnO microspheres shows high yield （〉90%） and good reproducibiliry. The formation process of ZnO microspheres was discussed. The as-obtained ZnO microspheres are expected to provide some immediate advantages for optical, microelectronic, and biological applications.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.40101017 and 40071048) by the Research Fund for the Doctoral Program of Higher Education(Grant No.2002050411).
文摘Single phase and well-crystallined todorokite were synthesized by heating and re-fluxing process from birnessite as a precursor. The average chemical composition of the synthe-sized todorokites by refluxing for 8 h and for 24 h was Mg0.19MnO2.11(H2O)1.15 and Mg0.17- MnO2.10(H2O)0.88, respectively. The crystallinity of the todorokite increased and no other phase was produced with increasing refluxing period. The synthesized todorokites have the same morphologies and the similar structural characteristics with the natural todorokites and hydro-thermally synthesized samples. The chemical compositions of the synthetic tordorokites by re-fluxing process are close to those of todorokites synthesized by hydrothermal process, except a higher average oxidation state of Mn for the former.
基金Supported by the National Natural Science Foundation of China(21576216,51372192)the Innovation Foundation from China Southern Power Grid(GDKJQQ20152050)
文摘Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.
