Photocatalytic Activity of PbS Quantum Dot/TiO2 Nanotube Composites

PbS quantum dots (PbS QDs) were attached to TiO 2 nanotubes on both the inside and outside surfaces of the nanotubes by using thiolactic acid, a bifunctional linker. The PbS QDs with diameters of 4−5 nm were controlled by adjusting the concentration of thiolactic acid. The PbS QDs can be placed only inside the nanotubes by first blocking the outer surface of the TNTs with the double-chain cationic surfactant. The photocatalytic activity and stability of PbS/TiO 2 nanotubes were evaluated for the photodegradation of organic dyes. The results indicate that the functionalized TiO 2 nanotubes were superior catalysts for photodegradation of cationic dyes. Additionally, the quantum dots enhance the activity and expand the usable portion of the solar spectrum.