Effective photocathodic protection for 304 stainless steel by PbS quantum dots modified TiO2 nanotubes

Using new photocathodic protection technology to protect 304 stainless steel has attracted extensive attention of corrosion researchers due to the severe resource consumption and economic loss caused by metal corrosion. However, the photocatalytic materials used for photocathodic protection still exist some defects such as high recombination rate and poor transfer efficiency of photoinduced electrons. Herein, PbS quantum dots modified TiO2 nanotubes photoelectrodes were successfully synthesized via electrochemical anodization combined with successive ion layer adsorption and reaction method. PbS(x)/TiO2 nanotubes (x = 2,4,6,8) samples were prepared by changing the deposition amounts of PbS. The results indicated that the PbS(6)/TiO2 nanotubes displayed a stronger photocurrent density of 3.2 mA cm−2 and the optical absorption red-shifted to the visible light region compared with pure TiO2. Moreover, a more negative open circuit potential was obtained when the PbS(6)/TiO2 nanotubes photoanode coupled with 304 stainless steel under visible light irradiation. The prepared composite films as a stable photoanode displayed highly effective photocathodic protection performance for 304 stainless steel.