Photocatalytic activity of quantum dots incorporated in molecular sieves for generation of hydrogen.

MCM-41 molecular sieve coupled with lead sulfide quantum dots (PbS-MCM-41) was prepared by ion-exchange method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, infrared spectroscopy (IR) and BET (Brunauer-Emmett-Teller) experiments. Exciton absorption peak at higher energy than the fundamental absorption edge of bulk lead sulfide indicates quantum confinement effects in quantum dots as a consequence of their small size. The hydrogen production rate from water photocatalytic decomposition under visible light irradiation (λ>400nm) over PbS nanoparticles formed in mesoporous material was much higher compared to the bulk PbS.