Photoelectrochemical performance of titania nanotubes codoped by vanadium and chromium for protection of stainless steel: A promising photoanode for continuous protection in the dark

Abstract

In this work, a (V, Cr)-co-doped titania nanotubes (TNTs)-based photoelectrode has been synthesized and used in the photoelectrochemical cathodic protection (PECCP) of 403 stainless steel (403SS). The photo-response of (V, Cr)-co-doped TNTs red-shifted to the range of visible light and their photocathodic protection for 403 Stainless Steel (403SS) was enhanced in comparison with pristine and undoped TNTs. A remarkably improved absorption for visible light was shown by the co-doped photoanode prepared in addition to considerably enhanced efficiencies of separation, transfer, and collection of photogenerated charges. Among the co-doped samples, sample V1 coupled with protected 403SS was found to be the most efficient photoanode. The open circuit potential of this sample under illumination has shifted from − 0.36 V to − 0.795 V with a 435 mV negative shift. However, the undoped TNTs sample only showed a 185 mV negative shift. In addition, a time-delay cathodic protection for 403SS can be provided by (V, Cr)-co-doped TNTs photoelectrode in the dark, which makes it potentially applicable in the industry, according to the results obtained.