Incorporation of Cu 5 FeS 4 QDs with Abundant Oxygen Vacancy TiO 2 QDs/TiO 2 OVs: Double S-Scheme Photocatalysts for Effectual N 2 Conversion to NH 3 under Simulated Solar Light.

Photocatalytic N 2 conversion to NH 3 is a green, sustainable pathway with renewable energy sources and carbon neutrality. In this research, ternary TiO 2 QDs/TiO 2 OVs/Cu 5 FeS 4 nanocomposites were prepared by an easy and affordable procedure and utilized to produce clean ammonia energy without a sacrificial agent. The amount of produced green ammonia by the optimum nanocomposite achieved was 17,274 μmol L -1 g -1 , which was approximately 20.9, 6.48, 4.45, 2.26, and 1.45 times higher than those of commercial TiO 2 , TiO 2 QDs, TiO 2 OVs, Cu 5 FeS 4 , and TiO 2 QDs/TiO 2 OVs photocatalysts, respectively. Lattice compatibility through the developed homojunction within TiO 2 QDs/TiO 2 OVs and the integration of Cu 5 FeS 4 nanoparticles led to the establishment of a double S-scheme homo/heterojunction system, which improved the photocatalytic activity by maintaining electrons and holes with high oxidation and reduction power and greatly reduced the recombination of charges, which led to the acceleration of charge transfer and migration. Besides, the promoted surface area compared to the pure components, introducing oxygen vacancies, and reducing the particle size boosted the photocatalytic N 2 conversion to NH 3 . The results of this research are a basis for the rational design of homojunction/heterojunction visible-light-responsive systems for photocatalytic nitrogen fixation reactions.