Pt quantum dots decorated nest-like 3D porous ZnO nanostructures for enhanced visible-light degradation of RhB

In this work, a novel Pt/ZnO composite: Pt quantum dots decorated nest-like 3D porous ZnO nanostructures has been prepared via a simple and effective method. The effect of loading Pt quantum dots on photocatalytic properties of ZnO nanostructures is investigated by using SEM, TEM, EDX, XPS, PL, UV-Vis DRS, and BET studies. The results show that nest-like 3D porous ZnO nanostructures can be rapidly synthesized at 80 celcius for 30 min under microwave heating. Subsequently, the metallic Pt quantum dots are successfully supported and uniformly distributed on the nest-like ZnO nanostructures by photochemical method to form the Pt/ZnO composite. The loading of Pt quantum dots on the nest-like 3D porous ZnO nanostructures intensively increases the visible light absorption resulting in about 4 times higher current response to the visible light, together with the BET surface area enhancement by 75%, than that of the pure ZnO. As a result, Pt/ZnO composite exhibits high catalytic stability and photocatalytic activity towards the degradation of Rhodamine B. In addition, the enhanced photocatalytic activity of Pt/ZnO is attributed to the Pt quantum dots acting as excellent photosensitizer and transporter of photogenerated electrons under visible light, which can retard the recombination of electrons and holes.