Gradient N-doping SrTiO3 photoanode with enhanced photoelectrochemical corrosion protection performance for 304 stainless steel

• Published in: Materials research bulletin 2025-03, Vol.183, p.113199, Article 113199
• Main Authors: Wang, Jiansheng, Qing, Da, Zhao, Yingna, Zeng, Xiongfeng
• Format: Article
• Language: English
• Subjects: Charge separation; Gradient N-doping; Homojunction; Photoelectrochemical corrosion protection; SrTiO3
• ISSN: 0025-5408
• DOI: 10.1016/j.materresbull.2024.113199

Low charge carrier separation is one of the prime factors limiting photoanode performance, and constructing homojunction in photoanode is an effective approach to accelerate charge carrier separation and transfer. In this work, we investigated the band structures of SrTiO3 with different concentrations of N doping. Based on the fact that SrTiO3 with different concentrations of N doping had different band structures, the homojunction was constructed by grading the N doping concentrations along the depth direction of SrTiO3, which was verified by cross-sectional SEM-EDS. SrTiO3 photoanode with forward gradient N-doping showed significantly improved charge separation efficiency and photoelectrochemical corrosion protection (PCP) performance for 304 stainless steel (304 SS). Under simulated sunlight, the open circuit potential of 304 SS in simulated seawater, when coupled with the a forward gradient N-doped SrTiO3 photoanode negatively shifted 250 mV at most, which was higher than that of reverse gradient N-doped SrTiO3 (80 mV) and homogeneous N-doped SrTiO3 (150 mV), showing effective protection for 304 SS. The forward gradient N-doped SrTiO3 photoanode shows excellent PCP performance due to gradient N-doping that constructs the built-in homojunction electric field along the depth direction, which expands the separation field range and accelerates carrier separation. [Display omitted]