Efficient Visible-Light-Driven Tetracycline Degradation and Cr(VI) Reduction over a LaNi1-XFeXO3 (0 < X < 1)/g-C3N4 Type-II Heterojunction Photocatalyst

The development of efficient, stable, and visible-light-responsive photocatalysts is crucial to address the pollution of water bodies by toxic heavy metal ions and organic antibiotics. Herein, a series of LaNi1-xFexO3/g-C3N4 heterojunction photocatalysts are prepared by a simple wet chemical method. Moreover, La-Ni0.8Fe0.2O3/g-C3N4 composites are characterized by various methods, including structure, morphology, optical, and electrochemical methods and tetracycline degradation and photocatalytic reduction of Cr(VI) under visible light irradiation. Then, the photocatalytic performance of as-prepared LaNi0.8Fe0.2O3/g-C3N4 composites is evaluated. Compared with pure LaNi0.8Fe0.2O3 and g-C3N4, the LaNi0.8Fe0.2O3/g-C3N4 composite photocatalysts exhibit excellent photocatalytic performance due to synergy of doping and constructing heterojunctions. The results show that the doping of Fe ions can increase the concentration of oxygen vacancies, which is ultimately beneficial to the formation of electron traps. Moreover, the type-II heterojunction formed between LaNi0.8Fe0.2O3 and g-C3N4 effectively strengthens the separation and transfer of photoinduced carriers, thereby promoting photocatalytic activity. Furthermore, the photocatalytic activity of the LaNi0.8Fe0.2O3/g-C3N4 photocatalyst remains almost unchanged after three cycles, indicating long-term stability. Ultimately, the photocatalytic mechanism of the LaNi0.8Fe0.2O3/g-C3N4 composites is proposed.

Automated summary

A series of LaNi1-xFexO3/g-C3N4 heterojunction photocatalysts were prepared by a simple wet chemical method and their structural, morphological, optical, electrochemical properties, as well as their photocatalytic degradation performance for tetracycline and Cr(VI), were investigated. The LaNi0.8Fe0.2O3/g-C3N4 composite photocatalysts exhibited excellent photocatalytic performance due to the synergy of doping and constructing heterojunctions. Doping of Fe ions increased the concentration of oxygen vacancies, favoring the formation of electron traps, while the type-II heterojunction formed between LaNi0.8Fe0.2O3 and g-C3N4 effectively enhanced the separation and transfer of photoinduced carriers, thereby promoting photocatalytic activity. The LaNi0.8Fe0.2O3/g-C3N4 photocatalyst showed long-term stability after three cycles of use, and a photocatalytic mechanism was proposed.