Synergy of Carbon Doping and Sulfur Vacancies Engineering in MOF-Derived Hollow Bi2S3 for High-Efficiency Photocatalytic Nitrogen Fixation

The development of efficient photocatalytic materials is the key to promoting the advancement and application of photocatalytic technology. Bi2S3, a relatively narrow bandgap semiconductor, can absorb visible light and even near-infrared light. However, the fast recombination rate of photogenerated electron–hole pairs, limited surface active sites, and susceptibility to photocorrosion of pure Bi2S3 severely restrict its photocatalytic efficiency. In this paper, carbon-doped sulfur-rich defective hollow Bi2S3 nanorods were prepared in one step using Bi-MOF as the precursor. The microcrystalline structure and defect structure were regulated by adjusting the hydrothermal reaction time. The ammonia production rate of hollow Bi2S3-2 under full sunlight was approximately 147.78 μmol·h–1·g–1. The superior photocatalytic activity of hollow Bi2S3-2 is mainly attributed to its sulfur defects, which can provide abundant active sites to activate nitrogen molecules. It reveals that the photoexcited electrons generate ammonia through two protonation pathways and weaken the N≡N bond in the photocatalytic nitrogen fixation path. This work provides new insights into photocatalytic nitrogen fixation and achieves efficient N2 photoreduction by synthesizing photocatalysts from MOF derivatives.