Spindle-like porous N-doped TiO2 encapsulated (Ca,Y)F2:Yb3+,Tm3+ as the efficient photocatalyst near-infrared range.

In this study, a novel photocatalyst composed of N-doped TiO2 (N-TiO2) and (Ca, Y)F2:Yb3+, Tm3+ was prepared by simple dealloying followed by a hydrothermal method. The composite exhibits a homogeneous nanoporous structure consisting of large quantities of the spindle-like N-doped TiO2 nanorods, on which the (Ca, Y)F2:Yb3+, Tm3+ particles with a diameter of around 5 nm are uniformly dispersed. In addition, morphology and property of the N-TiO2 can be controlled by adjusting the dealloying period. Results show that a short immersion time leads to a small size, large surface area and low band gap. As a result, the N-TiO2/(Ca, Y)F2:Yb3+, Tm3+ composite after dealloying for 48 h (TiO2-48-C) exhibits higher degradation rates (65.6% for 10 h irradiation by 980 nm NIR) than others after dealloying for 60 h (TiO2-60-C) and 72 h (TiO2-72-C), indicating its excellent potential for practical applications.