Assembly of WO3-Nb2O5-ZnIn2S4 with embedded quasi-planar heterojunction characteristics and its efficient and stable dark-state photoelectrochemical cathodic protection performance

Constructing a photoanode with both high dark-state protection performance and high stability remains a top priority for photoelectrochemical cathodic protection technology, especially in a marine environment (dark-state or rainy conditions) without hole scavenging agents. In this work, we developed a class of energy-storage quasi-planar heterojunctions (WO₃-Nb₂O₅-ZnIn₂S₄) with directional paths (low onset potential and well-matched energy band) and embedded morphology. The co-design of embedded and directional paths reduces the carrier transport energy barrier at the composite interface, and increases the interface contact area, thereby achieving highly stable and sensitive dark-state energy storage and photoelectrochemical cathodic protection performance in 3.5 wt.% NaCl solution without hole scavenging agent (Dark-state energy storage efficiency increased by 43%. For carbon steel, the performance retention rate is 99.6% after 500 cycles, the performance retention rate is 89% after 5000 s).