Efficient Visible-Light-Driven Tetracycline Degradation and Cr(VI) Reduction over a LaNi 1- x Fe x O 3 (0 ≤ x ≤ 1)/g-C 3 N 4 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 LaNiFeO/g-CN heterojunction photocatalysts are prepared by a simple wet chemical method. Moreover, LaNiFeO/g-CN 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 LaNiFeO/g-CN composites is evaluated. Compared with pure LaNiFeO and g-CN, the LaNiFeO/g-CN 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 LaNiFeO and g-CN effectively strengthens the separation and transfer of photoinduced carriers, thereby promoting photocatalytic activity. Furthermore, the photocatalytic activity of the LaNiFeO/g-CN photocatalyst remains almost unchanged after three cycles, indicating long-term stability. Ultimately, the photocatalytic mechanism of the LaNiFeO/g-CN composites is proposed.