CdS nanoparticles exhibiting quantum size effect by dispersion on tio 2: photocatalytic h 2 evolution and photoelectrochemical measurements

Abstract

Uniformly sized CdS nanoparticles exhibiting quantum size effect have been synthesized as a suspension in hexane solution containing oleic acid and 9-octadecenylamine as protective ligands. Our study focuses on utilizing the intrinsic optical property of the nanoparticles for photocatalytic H 2 evolution and photoelectrochemical reaction by immobilizing oxide substrate and removing protective ligands. Immobilized CdS nanoparticles on Ti0 2 were found to maintain their original particle size and optical property after impregnation and removal of the protective ligands by oxidative heat treatment and/or alkali treatment. The photocatalytic H 2 evolution rates in Na 2S-Na 2SO 3 solution under visible light were strongly affected by the CdS particle size (quantum size effect), CdS loading amount, and TiO 2 surface area. High photoanodic current was observed for CdS/Ti0 2 sprayed on a fluoride-doped tin oxide (FTO) electrode, functioning as an n-type semiconductor. The knowledge acquired in this study can be extended for further development in the field of nanoparticle materials covered with protective ligands. © 2009 The Chemical Society of Japan.