In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds ...In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.展开更多
The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light color...The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.展开更多
文摘In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.
文摘The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.
