Chemically bonded interface modulated S-scheme charge transfer in Sb2S3@ZnIn2S4 core–shell heterostructures for boosted catalytic activity toward nitrogen photofixation

Abstract

The exploration of efficient strategies for nitrogen photofixation driven by visible light at room temperature and atmospheric pressure is still highly desirable but remains a great challenge. In this study, hierarchical Sb₂S₃@ZnIn₂S₄ core–shell samples were synthesized through a hydrothermal reaction, in which ultrathin ZnIn₂S₄ nanosheets were tightly and uniformly wrapped on the surface of Sb₂S₃ nanorods. Systematic characterization revealed that the chemically bonded interface in Sb₂S₃@ZnIn₂S₄ core–shell heterostructures was critical to rapid charge separation, leading to a significant enhancement of photocatalytic performance for nitrogen photofixation. The optimal nitrogen photofixation system, namely, Sb₂S₃@ZnIn₂S₄-75, exhibited excellent performance achieving an ammonia concentration of 15.96 ± 0.97 mg L⁻¹ after visible light irradiation for 40 min, which was approximately 1.88 and 7.19 times higher than those of relevant ZnIn₂S₄ and Sb₂S₃, respectively. Moreover, an S-scheme charge transfer route on Sb₂S₃@ZnIn₂S₄ core–shell heterostructures was proposed based on band structure analysis, in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) investigation, noble metal deposition, and density functional theory (DFT) simulation. This work gave a useful insight into the development of efficient photocatalysts for boosted photocatalytic activity toward nitrogen photofixation.