Hydrolytic Modification of SiO(2) Microspheres with Na(2)SiO(3) and the Performance of Supported Nano-TiO(2) Composite Photocatalyst

Modified microspheres (SiO(2)-M) were obtained by the hydrolytic modification of silicon dioxide (SiO(2)) microspheres with Na(2)SiO(3), and then, SiO(2)-M was used as a carrier to prepare a composite photocatalyst (SiO(2)-M/TiO(2)) using the sol-gel method; i.e., nano-TiO(2) was loaded on the surface of SiO(2)-M. The structure, morphology, and photocatalytic properties of SiO(2)-M/TiO(2) were investigated. Besides, the mechanism of the effect of SiO(2)-M was also explored. The results show that the hydrolytic modification of Na(2)SiO(3) coated the surface of SiO(2) microspheres with an amorphous SiO(2) shell layer and increased the quantity of hydroxyl groups. The photocatalytic performance of the composite photocatalyst was slightly better than that of pure nano-TiO(2) and significantly better than that of the composite photocatalyst supported by unmodified SiO(2). Thus, increasing the loading capacity of nano-TiO(2), improving the dispersion of TiO(2,) and increasing the active surface sites are essential factors for improving the functional efficiency of nano-TiO(2). This work provides a new concept for the design of composite photocatalysts by optimizing the performance of the carrier.