Study on the Photoinduced Cathodic Protection of Ti/TiO2 Photoelectrodes Prepared by Microarc Oxidation with Silicate/Phosphate/Tungstate Electrolytes

The development of photoelectrode electronic structures and efficient charge-carrier separation is pivotal for the practical deployment of photoinduced cathodic protection (PICP) technology. Herein, the Ti/TiO2 composite photoelectrode Na2HPO4 + Na2SiO3 + Na2WO4 (PSW-TiO2) was fabricated via microarc oxidation (MAO) using a novel ternary electrolyte system. Benefiting from the synergistic effect of P, Si, and W codoping, the as-prepared ternary-modified electrode exhibits favorable PICP performance. Specifically, the corrosion potential of the coupled 304 stainless steel (304SS) shifts markedly from −0.71 V to −1.11 V under visible light irradiation. Electrochemical and spectroscopic analyses reveal that the coincorporation of heteroelements narrows the bandgap to 2.14 eV and optimizes the conduction band energy level, effectively suppressing the recombination of photogenerated carriers and accelerating interfacial charge transfer kinetics. Furthermore, 30-day accelerated salt-spray tests confirm the composite electrode’s improved thermodynamic stability and long-term service durability in harsh marine-simulating environments. This study provides a robust, scalable strategy for designing advanced photoelectrodes for sustainable corrosion mitigation of metals.