Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid i...Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid interfacial charge transfer. However,the present preparation methods usually include complicated and multistep procedures,which can cause damage to the hollow nanostructures. In this paper,a facile template-induced synthesis,based on a template-directed deposition and in situ template-sacrificial dissolution,was employed to prepare Ag-modified TiO 2（Ag/TiO 2） hollow octahedra using Ag2 O octahedra as templates and TiF 4 as the precursor. In the synthetic strategy,the shells of TiO 2 hollow octahedra were formed by coating TiO 2 nanoparticles on the surface of Ag2 O templates based on the template-directed deposition. Simultaneously,the Ag2 O templates can be in situ removed by dissolving the Ag2 O octahedral template in HF solution produced via the hydrolysis reaction of TiF 4 in the reaction system. In addition,Ag nanoparticles were deposited on the inside and outside surfaces of TiO 2 shells by effectively using the photosensitive properties of Ag2 O and Ag＋ ions under light irradiation,along with the formation of TiO 2 hollow octahedra. The Ag/TiO 2 hollow octahedra exhibited high photocatalytic activity because of their（1） short diffusion distances between photogenerated electrons and holes because of the thin shells of Ag/TiO 2 hollow octahedral,（2） deposition of Ag nanoparticles on the inside and outside surfaces of TiO 2 shells,and（3） rapid interfacial charge transfer between TiO 2 shells and Ag nanoparticles. This work may also provide new insights into preparing other Ag-modified and hollow nanostructured photocatalysts.展开更多
SnO2 hollow spheres have been synthesized via a facile hydrothermal method using sulfonated polystyrene beads as a template followed by a calcination process in air.X-ray diffraction,scanning electron microscopy,and t...SnO2 hollow spheres have been synthesized via a facile hydrothermal method using sulfonated polystyrene beads as a template followed by a calcination process in air.X-ray diffraction,scanning electron microscopy,and transmission electron microscopy show that the as-obtained SnO2 hollow spheres have a wall thickness of about 50 nm,and consist of nanosized SnO2 particles with a mean diameter of about 15 nm.Electrochemical measurements indicate that the SnO2 hollow spheres exhibit improved electrochemical performance in terms of specific capacity and rate capability in comparison with commercial SnO2 when used as anode materials for lithium-ion batteries.The enhanced performance may be attributed to the spherical and hollow structure,as well as the building blocks of SnO2 nanoparticles.展开更多
基金supported by the National Natural Science Foundation of China(5120839621277107+5 种基金21477094and 51472192)the Program for New Century Excellent Talents in University(NCET-13-0944)the Fundamental Research Funds for the Central Universities(WUT 2014-1a-0032014-VII-037and 2015IB002)~~
文摘Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid interfacial charge transfer. However,the present preparation methods usually include complicated and multistep procedures,which can cause damage to the hollow nanostructures. In this paper,a facile template-induced synthesis,based on a template-directed deposition and in situ template-sacrificial dissolution,was employed to prepare Ag-modified TiO 2（Ag/TiO 2） hollow octahedra using Ag2 O octahedra as templates and TiF 4 as the precursor. In the synthetic strategy,the shells of TiO 2 hollow octahedra were formed by coating TiO 2 nanoparticles on the surface of Ag2 O templates based on the template-directed deposition. Simultaneously,the Ag2 O templates can be in situ removed by dissolving the Ag2 O octahedral template in HF solution produced via the hydrolysis reaction of TiF 4 in the reaction system. In addition,Ag nanoparticles were deposited on the inside and outside surfaces of TiO 2 shells by effectively using the photosensitive properties of Ag2 O and Ag＋ ions under light irradiation,along with the formation of TiO 2 hollow octahedra. The Ag/TiO 2 hollow octahedra exhibited high photocatalytic activity because of their（1） short diffusion distances between photogenerated electrons and holes because of the thin shells of Ag/TiO 2 hollow octahedral,（2） deposition of Ag nanoparticles on the inside and outside surfaces of TiO 2 shells,and（3） rapid interfacial charge transfer between TiO 2 shells and Ag nanoparticles. This work may also provide new insights into preparing other Ag-modified and hollow nanostructured photocatalysts.
基金supported by the National Natural Science Foundation of China (21121063)the National Key Project on Basic Research(2011CB935700 and 2009CB930400)the Chinese Academy of Sciences
文摘SnO2 hollow spheres have been synthesized via a facile hydrothermal method using sulfonated polystyrene beads as a template followed by a calcination process in air.X-ray diffraction,scanning electron microscopy,and transmission electron microscopy show that the as-obtained SnO2 hollow spheres have a wall thickness of about 50 nm,and consist of nanosized SnO2 particles with a mean diameter of about 15 nm.Electrochemical measurements indicate that the SnO2 hollow spheres exhibit improved electrochemical performance in terms of specific capacity and rate capability in comparison with commercial SnO2 when used as anode materials for lithium-ion batteries.The enhanced performance may be attributed to the spherical and hollow structure,as well as the building blocks of SnO2 nanoparticles.
