Novel heterogeneous CdS nanoparticles/NiTiO3nanorods with enhanced visible-light-driven photocatalytic activity

Abstract

The narrow–narrow band gap semiconductor consisting of heterogeneous CdS nanoparticles/NiTiO₃ nanorods was fabricated by firstly synthesizing NiTiO₃ nanorods via an ethylene glycol-mediated route and then growing CdS nanoparticles on their surface through a chemical bath deposition method. The CdS nanoparticles and NiTiO₃ nanorods were in good contact and formed a heterogeneous composite as seen from SEM and TEM images. The heterogeneous CdS nanoparticles/NiTiO₃ nanorods possessed enhanced visible-light-driven photocatalytic activity in the photocatalytic reduction of highly toxic hexavalent chromium, compared to CdS nanoparticles and NiTiO₃ nanorods. The excellent photocatalytic performance was attributed to the large electric potential difference between the conduction bands of CdS and NiTiO₃, which was favorable for the photogenerated electron transport from CdS to NiTiO₃ and efficient photogenerated charge separation at the heterogeneous interface. Moreover, the heterogeneous composites were very stable because the photocatalytic activity remained nearly constant after five cycles, which was favorable for practical applications.