Synergistic manipulation of micro-nanostructures and composition: Anatase/rutile mixed-phase TiO_2 hollow micro-nanospheres with hierarchical mesopores for photovoltaic and photocatalytic applications

摘要

The construction of nanocrystals with controllable composition and desirable micro-nanostructures is a well-known challenge. A combination of favorable composition and optimized micro-nanostructures can enhance the performance of a material significantly. Using TiO_2 as an example, we demonstrate here a facile approach to prepare anatase/rutile mixed-phase TiO_2 hollow micro-nanospheres with hierarchical mesopores. Our strategy relies on polymer-assisted assembly of ～ 5nm nano-building blocks into three-dimensional hierarchical hollow micro-nanospheres in a mixed alcohol-water solution. This superior micro-nanostructure endows the sample with hierarchical mesopores and a high surface area of 106 m~2g ~(-1). We also show that, due to the synergetic effects of the mixed-phase composition and the micro-nanostructures, the sample exhibited significantly improved photovoltaic performance and similar photocatalytic performance compared with the commercial Degussa P25. These results suggested that our sample has great potential for future photovoltaic and photocatalytic applications.