Metastable β-Bi₂O₃ exhibits high catalytic performance due to its suitable band gap, greater dielectric permittivity and conductivity. However, the difficultly in preparing β-Bi₂O₃ and β-Bi₂O₃ based materials is still a problem to be overcome. In this work, porous Bi/β-Bi₂O₃@Carbon photocatalysts were prepared for the first time by using atmosphere switching strategy during the post-cooling of metal-organic framework (MOF) pyrolysis. The crystal phase structure and composition of Bi/β-Bi₂O₃@Carbon could be easily adjusted by simply switching cooling atmosphere from N₂ to air when cooled to different temperatures. The photocatalytic activities of the material were evaluated by degradation of emerging pollutant Fluorescent whitening agents (FWA) 351 under simulated solar light irradiation. It was observed that 10 mg/L FWA 351 was completely degraded within 4 h using the optimal photocatalyst. The mineralization efficiency reached 60% in 6 h. Active species trapping experiments confirmed that hole oxidation was responsible for the degradation of FWA 351. The increased activity was due to the improved visible light utilization resulted from reduced bandgap of Bi/β-Bi₂O₃@Carbon and surface plasmon resonance effect of bismuth metal, as well as the facilitated interfacial electron migration and charge carrier separation through multi-interface transfer paths. The proposed strategy provides new ideas for designing and synthesizing functional materials. The efficient degradation and mineralization of FWA 351 by Bi/β-Bi₂O₃@Carbon also confirmed its potential for future application in wastewater treatment.

中文翻译：

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合成 Bi/β-Bi2O3@Carbon 的新途径：高效降解有机污染物的机理和性能


亚稳态 β-Bi₂O₃ 由于其合适的带隙、更大的介电常数和导电性而表现出高催化性能。然而，制备 β-Bi₂O₃ 和 β-Bi₂O₃ 基材料的困难仍然是一个需要克服的问题。在本工作中，在金属有机框架 （MOF） 热解后冷却过程中，首次采用气氛切换策略制备了多孔 Bi/β-Bi₂O₃@Carbon 光催化剂。当冷却到不同的温度时，只需将冷却气氛从 N₂ 切换到空气，即可轻松调整 Bi/β-Bi₂O₃@Carbon 的晶相结构和组成。通过在模拟太阳光照射下降解新兴污染物荧光增白剂 （FWA） 351 来评价材料的光催化活性。观察到 10 mg/L FWA 351 使用最佳光催化剂在 4 小时内完全降解。6 h内矿化效率达到60%。活性物质捕获实验证实，空穴氧化是 FWA 351 降解的原因。活性的增加是由于 Bi/β-Bi₂O₃ 的带隙降低和铋金属的表面等离子体共振效应@Carbon以及通过多界面转移路径促进界面电子迁移和电荷载流子分离导致可见光利用率的提高。所提出的策略为设计和合成功能材料提供了新思路。 Bi/β-Bi₂O₃@Carbon 对 FWA 351 的高效降解和矿化也证实了其未来在废水处理中应用的潜力。