NaYF4:Yb,Tm/CdS composite as a novel near-infrared-driven photocatalyst
We report on the preparation of a novel near infrared photocatalyst by combining a low energy band gap semiconductor CdS with an upconversion material NaYF4:Yb,Tm. Particles of CdS and NaYF4:Yb,Tm are pretreated with thioglycolic acid and mercaptoethanol. The reaction between these two organic molecules causes the formation of NaYF4:Yb,Tm/CdS composite. Results from scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and powder X-ray diffraction (XRD) measurements demonstrate that CdS nanoparticles are uniformly assembled on the surface of NaYF4:Yb,Tm microrods. Energy transfer from NaYF4:Yb,Tm to CdS is confirmed by the upconversion and fluorescence decay properties. Hydroxyl radicals are generated upon NIR irradiation on the composite material. The NIR photocatalytic activity of the NaYF4:Yb,Tm/CdS composite is investigated by degrading Rhodamine B and methylene blue. A mechanism for NIR-driven photocatalysis is proposed.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ CdS nanoparticles are deposited uniformly onto NaYF4:Yb,Tm microrods. ▶ Upon NIR irradiation, NaYF4:Yb,Tm emits visible-light that absorbs by CdS. ▶ NIR-induced photocatalysis is realized by using the new composite material.
Journal: Applied Catalysis B: Environmental - Volume 100, Issues 3–4, 20 October 2010, Pages 433–439