Novel Bi2S3/Bi2O2CO3 heterojunction photocatalysts with enhanced visible light responsive activity and wastewater treatment

Abstract

Novel Bi₂S₃/Bi₂O₂CO₃ heterojunction photocatalysts were prepared by a simple chemical reaction from commercial Bi₂O₂CO₃. The photocatalytic activities of Bi₂S₃/Bi₂O₂CO₃ were evaluated by degrading Rhodamine B (RhB) under visible light and sunlight irradiation. Further investigation revealed that the content of loading bismuth sulfide (Bi₂S₃) had important effects on the photocatalytic activity of the Bi₂S₃/Bi₂O₂CO₃ heterojunctions, and the 5 mol% Bi₂S₃/Bi₂O₂CO₃ heterojunction photocatalyst exhibited the best photocatalytic activity (30 min under visible light, λ > 400 nm). The high photocatalytic activity could be attributed to its good visible light absorption, facilitated charge separation of photogenerated electron–hole pairs and efficient charge transfer path in the partly exposed core in the heterojunctions. These benefits are derived from the unique band gap structure of the Bi₂S₃/Bi₂O₂CO₃ n–n-type heterojunctions and special morphology with the partly exposed core, which was confirmed by photoluminescent spectra, surface photovoltage spectra and photoelectrochemical characterizations.