A facile synthesis of CdSe quantum dots-decorated anatase TiO2 with exposed {001} facets and its superior photocatalytic activity

摘要

Anatase TiO2 with exposed {001} facets (denoted as T001) is becoming one of the hotspots in photocatalytic field due to the highly reactive {0 01} facets. Nowadays, to further extend the applications of T001 in visible region, researchers are struggling to develop T001-based visible-light-responsive photo-catalysts. In this paper, for the first time, CdSe quantum dots (QDs)-decorated T001 (denoted as CS-T001) was synthesized successfully via a facile method and demonstrated as a highly efficient and stable photocatalyst for reduction of nitro aromatics under visible light irradiation. Besides the obviously extended light absorption in visible region, the decoration of CdSe QDs onto T001 would remarkably improve the transfer and separation efficiency of photogenerated charge carriers, resulting in the much higher activity of CS-T001 as compared with pure T001 and CdSe QDs. Serving as the accepted sites for photoelectrons generated from CdSe QDs, the substrate T001 also plays a vital role. First,T001 offers highly active reaction sites due to the much higher surface energy of {0 0 1} facet than that of {1 01} facet. Second, compared with CdSe QDs-decorated anatase TiO2 with exposed {1 01} facets (denoted as CS-T101), CS-T001 can generate electrons with stronger reducibility to participate in the photocatalytic reduction process. Third, the aggregation of T001 nanosheets gives rise to the porous structures with slit-like pores, providing efficient transport pathways to reactant and product molecules. Fourth, CS-T001 possesses much higher separation efficiency of photogenerated charge carriers as compared to CS-T101. We believe that our work could not only provide a facile method for fabricating novel QDs-decorated T001 photocatalysts but also help us to realize the synergy between decoration of QDs and exposure of TiO2 {001} facets during the photocatalytic reaction process. (C) 2015 Elsevier B.V. All rights reserved.