Review of TiO₂-Based Heterojunction Coatings in Photocathodic Protection

Abstract

Photocathodic protection coating is an emerging anticorrosion technology that combines the protective characteristics of coating and cathodic protection. TiO 2 is stable and easy to prepare; however, it suffers from a low sunlight utilization rate and low photoelectric conversion efficiency. The construction of TiO 2 -based heterojunction coatings provides an effective solution to these challenges. This work summarizes the synthesis methods of TiO 2based heterojunction coatings, explores the charge-transfer mechanisms associated with various types of heterojunction coatings (e.g., type II heterojunction, p−n junction, Schottky junction, and Z-scheme heterojunction), and reviews the characterization methods used for heterojunction analysis. Finally, the application prospects and future research directions of TiO 2 -based heterojunction coatings are proposed. This study will help researchers understand the fabrication process and application of TiO 2 -based heterojunction coatings in photocathodic protection.