TiO₂ Quantum Dots/Fe₃S₄ Heterojunction Nanocomposites for Efficient Ammonia Production through Nitrogen Fixation upon Simulated Sunlight

Using semiconductor photocatalysts instead of the traditional Haber–Bosch procedure to produce ammonia is a promising strategy to save energy and prevent environmental pollution. Therefore, finding a suitable photocatalyst with high efficiency and stability has become one of the big challenges of research communities in the field of heterogeneous photocatalysis. Herein, S-scheme TiO 2 quantum dots (QDs)/Fe 3 S 4 heterojunction photocatalysts were synthesized through a hydrothermal route. The nitrogen photofixation measurements exhibited that the TiO 2 QDs/Fe 3 S 4 photocatalysts have excellent activities, where the generation of NH 3 by the optimized nanocomposite reached 16,624 μmol L –1 g –1 upon simulated sunlight. This amount was almost 19.9, 6.30, and 2.85 times as high as those of TiO 2, TiO 2 QDs, and Fe 3 S 4 photocatalysts, respectively. The promoted photocatalytic ability was devoted to outstanding visible-light absorption, accelerated segregation of photoinduced electron–hole pairs, and enhanced surface area. The key purpose of this research was the rational design of a photocatalyst based on TiO 2 QDs through a one-pot and facile fabrication procedure, which exhibits admirable performance in the field of photocatalytic nitrogen fixation. Considering the advantages of binary TiO 2 QDs/Fe 3 S 4 photocatalysts, it is anticipated that this photocatalyst could be utilized in solar energy conversion processes.