<p>Photocatalytic cathodic protection technology involves the generation of photo-generated electrons by photovoltaic materials under illumination, providing cathodic polarization to the protected metal and thereby inhibiting its corrosion. However, issues such as the wide bandgap, rapid recombination of electrons and holes, lacking charge storage capabilities, along with the practical applications results in certain challenges. In this study, TiO₂ nanotube arrays doped with different molar ratios of Ce and Co (Ce_x-Co_y/TiO₂) were synthesized using a one-step anodization method. The results indicate that under illumination conditions, when carbon steel is coupled with Ce₁-Co₁/TiO₂, its open-circuit potential (OCP) shifts negatively by approximately 300 mV and 150 mV relative to the uncoupled carbon steel photoanode materials and the coupled pure TiO₂ conditions, respectively.The photocurrent density shows the 2.4 times higher than that of pure TiO₂. Additionally, even when the light source was turned off, it could still provide a continuous cathodic protection for carbon steel. The enhanced photocathodic protection can be attributed to the nonlinear distribution of Ce and Co on the Ce_x-Co_y/TiO₂ surface with the gradient transition from reduced states to oxidized states at interface, which enhances the system’s light-harvesting capability and forms a heterojunction with TiO₂, which enhances the separation and migration of photogenerated charge carriers. This study provides a general design and preparation scheme for the application of semiconductor composite materials in the field of photocathode corrosion protection.</p>