Design of New Al Photoanode Composite for Cathodic Protection Based on Photocatalytic Material and Sacrificial Anode

Abstract

A new kind of Al photoanode composite based on photocatalytic material and sacrificial anode was proposed and designed to provide new ideas for cathodic protection in marine environment. Fabricated with the traditional Al-Zn-In-Mg-Ti sacrificial anode and Co(OH)2 modified anatase TiO2 nanotubes, a new Al photoanode composite with good photoelectrochemical cathodic protection property was obtained. To compare with the traditional sacrificial anode, the cathodic protective properties of both the sacrificial anode and this Al photoanode composite were evaluated by electrochemical measurements in aqueous 3.5 wt.% NaCl solution. By means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectrophotometer morphologies, crystal structures, surface compositions and light response range of the Al photoanode composite during the immersion were characterized, respectively. The generated protective current density of the Al photoanode composite is found to be greater under illumination than that of the traditional Al-Zn-In-Mg-Ti sacrificial anode. Co(OH)2@TiO2 plays an important role in supplemental protection for Q235 carbon steel and improves the current efficiency.