Construction of nano-TiO2 decorated titanosilicate core-shell structure: Highly efficient oxygen activation for the degradation of Rhodamine B under visible light and excellent recycling performance

Abstract To improve the photocatalytic performance of TiO2 and make it easier to recycle, the titanosilicate@anatase core-shell micro-nanostructure photocatalysts were designed. The titanosilicate@anatase core-shell micro-nanostructure was fabricated by a two-step method: an acid-assisted hydrothermal treatment of the hydrogen-form natisite and a subsequent calcination. In the first step, the dissolution and recrystallization of Ti species led to the formation of TiO2 shell over the titanosilicate; in the second step, the calcination not only facilitated the formation of Ti−O−Si bond, but also improved the crystallization of TiO2 shell. The rutile TiO2 was not detected even at 900 °C, which could be attributed to the strong interaction between TiO2 nanocrystals and the titanosilicate core through Ti−O−Si bond at the interface. The formation of Ti−O−Si bond also changed the surface characteristic of the TiO2 shell, which facilitated the enrichment of RhB dye molecules around the catalyst and induced the fast production of the O2•−. The collaboration of the core and the shell contributed to the quick degradation of RhB under visible light and the excellent recycling performance. The growth kinetics of the core-shell micro-nanostructure has been studied in detail, which provided a novel and facile synthesis strategy for the fabrication of TiO2 micro-nanostructure easy to be recycled.