In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： firs...In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： first, hollow polymer spheres with large hollow interior were prepared using sodium oleate as the hollow core generator, and 2,4-dihydroxybenzoic acid and hexamethylene tetramine （HMT） as the polymer precursors under hydrothermal conditions; Fe3＋ or Ag＋ cations were then introduced into the as-prepared hollow polymer spheres through the carboxyl groups; finally, the hollow polymer spheres can be pseudomorphically converted to hollow carbon spheres during pyrolysis process, meanwhile iron or silver nanoparticles can also be formed in the carbon shell simultaneously. The structures of the obtained functional hollow carbon spheres were characterized by TEM, XRD, and TG. As an example, Ag-doped hollow carbon spheres were used as colloid catalysts which showed high catalytic activity in 4-nitrophenol reduction reaction.展开更多
A simple and versatile synthesis method was developed to prepare inorganic multi-metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides （LDH） with pre-determined ...A simple and versatile synthesis method was developed to prepare inorganic multi-metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides （LDH） with pre-determined compositions were used as precursors for multi-metal oxides and carbon spheres （CSs） prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core-shell structures. Finally, multi-metal oxides with hollow spherical structures were obtained by calcination, These hollow spheres were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, trans- mission electron microscope （TEM） and inductively coupled plasma （ICP）. Results revealed that the as-prepared oxide hollow spheres could exactly inherit the metal-to-metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi-component ones, including MgO/Ak2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3.展开更多
基金supported by NSFC (No. 20873014 and 21073026)the Program for New Century Excellent Talents in University of China (NCET-09-0254)
文摘In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： first, hollow polymer spheres with large hollow interior were prepared using sodium oleate as the hollow core generator, and 2,4-dihydroxybenzoic acid and hexamethylene tetramine （HMT） as the polymer precursors under hydrothermal conditions; Fe3＋ or Ag＋ cations were then introduced into the as-prepared hollow polymer spheres through the carboxyl groups; finally, the hollow polymer spheres can be pseudomorphically converted to hollow carbon spheres during pyrolysis process, meanwhile iron or silver nanoparticles can also be formed in the carbon shell simultaneously. The structures of the obtained functional hollow carbon spheres were characterized by TEM, XRD, and TG. As an example, Ag-doped hollow carbon spheres were used as colloid catalysts which showed high catalytic activity in 4-nitrophenol reduction reaction.
基金Natural Science Foundation of Shanghai (10ZR1413400)"Chen Guang" project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation Science & Technology (09CG53)+1 种基金Science & Technology Program of Shanghai Maritime University (2008450)Science Foundation for The Excellent Youth Scholars of Shanghai Municipal Education Commission~~
文摘A simple and versatile synthesis method was developed to prepare inorganic multi-metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides （LDH） with pre-determined compositions were used as precursors for multi-metal oxides and carbon spheres （CSs） prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core-shell structures. Finally, multi-metal oxides with hollow spherical structures were obtained by calcination, These hollow spheres were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, trans- mission electron microscope （TEM） and inductively coupled plasma （ICP）. Results revealed that the as-prepared oxide hollow spheres could exactly inherit the metal-to-metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi-component ones, including MgO/Ak2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3.
