Rapid microwave-assisted hydrothermal synthesis of hierarchical micro/nanostructured TiO2 with tunable nanomorphologies

Abstract

Anatase hierarchical micro/nanostructured TiO2 was successfully prepared by a rapid (10 min) one-pot microwave-assisted hydrothermal method. The nanomorphologies (including the exposed crystal facets) of the as-prepared TiO2 samples could be facilely tuned in the reaction system. The possible formation mechanism of the hierarchical micro/nanostructured TiO2 were discussed in detail, it was found that the chelating role of EDTA could control the slow release of Ti4+-containing species, providing a large space for the controlling of crystallite size and complex nano-morphologies. Moreover, an interesting “crystal facets-dependent photocatalytic selectivity” was found, in which the photocatalytic selectivity could be tuned by modifying the exposed crystal facets of TiO2. With the unique structural properties, the hierarchical micro/nanostructured TiO2 prepared by the present microwave-assisted hydrothermal method might also show potential application in more fields, such as dye-sensitized solar cells, gas sensing and lithium ion batteries, and the present microwave-assisted hydrothermal method could be further used in the rapid synthesis of other inorganic functional nanomaterials with complex hierarchical micro/nanostructures.