Highly efficient CdSe/CdS co-sensitized TiO2 nanotube films for photocathodic protection of stainless steel

A ZnS/CdSe/CdS/TiO2 composite nanotube film on titanium substrates was prepared by an anodic oxidation method and a chemical bath deposition technique in succession. This CdSe/CdS co-sensitized TiO2 nanotube film was used as a photoanode to achieve a special photocathodic protection effect for metals. The ZnS shell was deposited onto the film to cover the CdS and CdSe quantum dots so as to improve their stabilities. The results indicated that the photoabsorption of the composite film shifted to the visible region and the photocurrent intensity was greatly enhanced due to the modification of CdS and CdSe quantum dots. Especially when 403 stainless steel in a 0.5 M NaCl solution was coupled to the ZnS/CdSe/CdS/TiO2 film photoanode, its potential decreased by 1100 mV under white light illumination, which indicated that the composite film could produce highly efficient photocathodic protection for the steel. (C) 2012 Elsevier Ltd. All rights reserved.