Rational design of a broadband-responsive core-shell Sb2S3/BiOBr S-scheme heterojunction for simultaneous H2O2 production and tetracycline hydrochloride degradation

Abstract

The development of photocatalytic systems capable of simultaneously generating H₂O₂ and degrading pollutants presents an effective strategy for tackling concurrent energy and environmental crises. Herein, we report a visible-light-responsive core-shell Sb₂S₃/BiOBr (SS/BOB) S-scheme heterojunction that synergistically couples solar-driven H₂O₂ generation with tetracycline hydrochloride (TCH) mineralization, eliminating the need for external sacrificial agents. The architecture features one-dimensional Sb₂S₃ microrods as a light-harvesting core, encapsulated by BiOBr nanoparticles via in situ precipitation, creating intimate interfacial contact and enhanced light absorption. Comprehensive characterization, including ESR, in-situ irradiated XPS, and radical trapping experiments, confirms the establishment of an S-scheme charge transfer mechanism. In this mechanism, low-energy electrons in the conduction band of BiOBr recombine with low-energy holes in the valence band of Sb₂S₃ at the interface, preserving high-reduction-potential electrons in Sb₂S₃ for efficient indirect two-electron oxygen reduction to yield H₂O₂ and high-oxidation-potential holes in BiOBr for direct TCH oxidation and •OH generation. The optimized SS/BOB-0.6 composite exhibits a high H₂O₂ yield of 419.54 µmol L⁻¹ in a 60 mg L⁻¹ TCH solution within 2 h, which is 2.71 times higher than that obtained in isopropanol, and concurrently removes 84.50% of TCH. This work develops a photocatalytic approach that transforms antibiotic-contaminated wastewater into a valuable source of green oxidant, offering a new design principle for multifunctional S-scheme heterojunctions in integrated solar-to-chemical conversion and environmental remediation.

Graphical abstract