Hollow B-SiO

2

@TiO

2

composites were prepared by the wet chemical deposition method starting from TiCl

4

and hollow B-SiO

2

microspheres. TiO

2

layers composed of anatase TiO

2

nanoparticles were coated on the surfaces of the hollow B-SiO

2

microspheres probably through the formation of Ti-O-Si and Ti-O-B bonds. A great number of-OH groups were also present at the TiO

2

coating layers. The presence of Ti-O-Si bonds and Ti-O-B bonds resulted in the formation of defects in the TiO

2

coating layers

which decreased the band gap of the TiO

2

coating layers to ca. 3.0 eV and endowed the TiO

2

coating layers with visible light absorption performance. The buoyancy hollow B-SiO

2

@TiO

2

composites exhibited high photocatalytic activities for the degradation of ammonia-nitrogen and green algae. The conversion of ammonia-nitrogen reached 65% when the degradation of ammonia-nitrogen (43 mg·L

-1

at pH value of 8) was catalyzed by the B-SiO

2

@TiO

2

(100:10) composite under the simulated solar light irradiation at 35℃ for 660 min. The green algae (5 mg·L

-1

) were almost completely degraded over the B-SiO@TiO

2

(100:20) photocatalyst under the visible light irradiation at 35℃ for 510 min.