Construction and excellent photoelectric synergistic anticorrosion performance of Z-scheme carbon nitride/tungsten oxide heterojunctions

Abstract

The use of heterojunctions for metal corrosion protection is a highly innovative and challenging task. Based on the composition and structure of tungsten oxide-based heterojunctions, Z-scheme heterojunctions were designed and synthesized by the electrostatic self-assembly method using energy band-matched g-C₃N₄ and WO₃ materials. Applied in the field of anticorrosion, they overcame the problems of poor reduction ability and transmission inefficiency of traditional materials. The Z-scheme heterojunctions ensured unidirectional electron transfer, while the aggregation of the retained strongly reduced electrons on the surface of the iron substrates provided a strong driving force for retarding corrosion occurrence. Meanwhile, the inherent shielding properties of the two-dimensional material g-C₃N₄ and the confinement of chloride ions as an electroactive layer hindered the penetration of the corrosive solution. After being corroded for 72 h, the corrosion impedance of the g-C₃N₄/WO₃ heterojunction system was improved by 640.11% compared with the epoxy resin coating. In addition, the g-C₃N₄/W₁₈O₄₉ heterojunction was synthesized by using mixed valence tungsten oxide, which overcame the problems of photogenerated electron yield and lifetime, and enhanced the anticorrosion performance compared with a single g-C₃N₄ phase. This research provided ideas for designing efficient and environmentally friendly heterojunction anticorrosion materials.