High visible-light rhodamine B degradation activity over two-dimensional Bi₂O₂CO₃/BiOCl heterojunction through the cohesive and efficient electronic transmission channel

Strategies of bridging electronic transmission channel have been widely applied in photocatalyst design to optimize the charge transportation processes. However, the contact area and interfacial interaction between two catalysts still required to be enlarged and strengthened to further improve that process. In this work, two-dimensional Bi₂O₂CO₃/BiOCl composites were fabricated through a facile chemical method at room temperature. According to the photocatalytic activity evaluations, the optimized Bi₂O₂CO₃/BiOCl composite exhibited excellent activity and achieved complete degradation of Rhodamine B (RhB) within 5 min while only 52% was degraded by Bi₂O₂CO₃ in 25 min under visible light irradiation. The mechanism of enhanced activity were investigated and discussed in detail which can be attributed to two aspects. First, the matched band structure of Bi₂O₂CO₃/BiOCl heterojunction provided new pathway for photo-induced electrons, which produced superoxide radical (·O₂⁻) and hydroxyl radical (·OH) for degradation of RhB. Second, the in situ-formed BiOCl has strong cohesion with {001} facet of Bi₂O₂CO₃ thus generating the stacked sandwich structure. This structure provided carriers with long lifetime with the assistance of electronic transmission channel formed between Bi₂O₂CO₃ and BiOCl as well as a larger contact area. As a result, the interfacial charge recombination was efficiently suppressed. With these two factors, the visible-light-induced RhB degradation of Bi₂O₂CO₃/BiOCl was promoted. This work provided an effective strategy for photocatalyst design. And the low cost and facile fabrication strategy also offered a promising potential of Bi-based catalyst in photocatalytic application.