In-situ generation of Bi2S3 to construct WO3/BiVO4/Bi2S3 heterojunction for photocathodic protection of 304SS

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2022-02, Vol.907, p.116033, Article 116033
• Main Authors: Guo, Huixia, Zhang, Yurong, Wang, Shan, Li, Liangliang, Wang, Weiming, Sun, Qinshuo
• Format: Article
• Language: English
• Subjects: 304SS; Bismuth oxides; Bismuth sulfides; Heterojunctions; In-situ generation; Photocathodic protection; Photoelectrochemical devices; Semiconductor materials; Sodium sulfide; Spin coating; Ternary heterojunction WO3/BiVO4/Bi2S3; Vanadates
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2022.116033

•WO3/BiVO4 was synthesized by spin coating and hydrothermal method.•WO3/BiVO4/Bi2S3 was constructed in situ in the photocathodic protection tests.•The OCP of 304SS coupled with WO3/BiVO4 reduced to −690 mV.•The protection on 304SS in the dark could last for 10 h. Photocathodic protection, benefiting from semiconductor materials with outstanding photoelectrochemical characteristics, has raised extensive attention because of its energy-saving and environment-protecting properties. In this work, WO3/BiVO4 composite film was synthesized by spin coating and hydrothermal method. BiVO4 in the composite film reacted with Na2S, used as electrolyte in the photoelectrochemical cell, to generate Bi2S3in-situ, and constructed a ternary heterojunction WO3/BiVO4/Bi2S3. As a photoelectrode, it boosted photocathodic protection performance for 304SS. The results revealed that the OCP of 304SS coupled with the heterojunction in 3.5 wt% NaCl solution could be further reduced to −690 mV, as well as it could protect 304SS steadily up to 10 h in the dark. The above could be attributed to alleviating the recombination and promoting the separation of photogenerated carriers. This work provides unique reference for constructing photoanodes on photocathodic protection of metal.