Research on Regulation Mechanism of TiO₂ Photocathodic Protection Based on Cohesive Energy, Defect Patterns, and Nanofilm Size

Anatase TiO₂ finds diverse applications in high-efficiency photocatalysis, high light efficiency, and photoinduced cathodic protection. Nevertheless, TiO₂'s wide band gap and high recombination rate of photogenerated carriers hinder its application in photocathodic protection. In this study, we propose a strategy to regulate the bandgap and carrier recombination of TiO₂ based on cohesion energy and defect patterns. Our findings indicate that the regulation of nanoparticle size and vacancy concentration can be determined using strategies and first-principles calculations. The optimal oxygen vacancy concentration is approximately 1/108. With an increasing vacancy concentration, the cohesive energy and vacancy formation energy of TiO₂ nanoparticles decrease, leading to reduced stability of the anatase phase and shorter photoelectron-hole lifetimes. Furthermore, sample D-6 exhibited superior photocathodic protection performance. These findings suggest that our regulation strategy effectively enhances the bandgap and carrier properties of anatase TiO₂ for use in photocathodic protection materials.