Zn-Cu-In-Se quantum dots sensitized the etched and W-doped TiO2 nanoflowers with highly exposed {0 0 1} facets for superior photocatalytic performance

Abstract

Herein, a high-performance composite photocatalyst was fabricated by using the three-dimensional TiO2 nanoflowers dominated by high-energy {001} facets as template and the emerging four-element Zn-Cu-In-Se (ZCISe) quantum dots (QDs) as sensitization material. The highly exposed high-energy {001} facets were more favorable for the adsorption reaction of organic pollutants, and which can form the unique surface heterojunctions to promote the charge transport. Before sensitizing ZCISe QDs, the surface characters and electronic structure of TiO2 nanoflowers were further optimized by a synchronous etching and W-doping treatment, thereby bringing in larger surface area, more active sites, proper impurity levels and increased electron density. Benefiting by the excellent surface properties, the ZCISe QDs were uniformly loaded on the surface of the etched and W-doped TiO2 (EWT) nanoflowers, and the high-quality TiO2/ZCISe heterojunctions with good interface connection were formed. In comparison to pure TiO2 nanoflowers, EWT@ZCISe composites exhibited significantly improved photocatalytic abilities for Rhodamine B (Rh B) under visible light. It was mainly related to the remarkable improvements in the light capture capability and the charge transport and separation characteristics. The optimal degradation rate of EWT@ZCISe composite for Rh B researched to 97.6% within 50 min, which is about 2.51 times higher than that of pure TiO2 nanoflowers. Additionally, the enhanced photocatalytic mechanism was also discussed in depth.