Synthesis of the Hollow Silica Nanospheres and P, Al and Yb Co-Doped Silica for Optical Fiber Preform.

The hollow silica nanospheres were synthesized by the template method and sol-gel method with ammonium hydroxide as base catalysts. Phase compositions, microstructures and specific surface area of the products were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), field emission transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS) and Brunauere-Emmette-Teller (BET). The results show that the hollow silica nanospheres synthesized with 10 ml polystyrene-methylacrylic acid latex, 116.13 ml absolute ethanol, 11.16 ml tetraethyl orthosilicate and 2 ml NH3 · H2O as raw materials were even spherical particles and around 150 nm, and the specific surface area is 160.699 m2 · g-1. The P, Al and Yb co-doped silica was prepared by vacuum inhaling and nitrate coating method with the hollow silica nanospheres and solid silica nanospheres as raw materials. The results show that the P, Al and Yb co-doped silica prepared using the hollow silica nanospheres had higher the molar ratio of phosphorus to silicon than using the solid silica nanospheres, and the phosphorus had rather uniform distribution on the silica surface, it shows that this method can improve the phosphorus retention ratio of materials. This study would provide a way to preparing the P, Al and Yb co-doped silica by sol-gel method with ammonium hydroxide as base catalysts.