Intimately coupled photocatalytic biodegradation (ICPB) has been recently developed as an efficient wastewater treatment technique, particularly for removing persistent organic pollutants. However, photocatalyst/biofilm interaction in terms of photoelectron transfer and its effect on the overall performance of ICPB has not been explored. To investigate these points, interface-engineered composites of bismuth vanadate and reduced graphene oxide with low degree (BiVO₄/rGO-LC) and high degree of their contact (BiVO₄/rGO-HC) were fabricated and applied for ICPB. As a result, the composites displayed interface-dependent optical, structural and charge carrier separation properties. The photoelectrochemical measurements confirmed the presence of photoelectron shunting between photocatalyst and biofilm, while the current density was higher (smaller Nyquist arc) for BiVO₄/rGO-HC than BiVO₄/rGO-LC and BiVO₄ in ICPB protocol, confirming the crucial role of intimate interfacial contact for photoelectron shunting from BiVO₄ to biofilm. Consequently, the presence of graphene and its interfacial quality dictated the photoelectron shunting between photocatalyst and biofilm, enhancing photoelectron-holes separation and achieving superior degradation rate of tetracycline hydrochloride for BiVO₄/rGO-HC (0.031 h^-1) compared to BiVO₄/rGO-LC (0.013 h^-1) and BiVO₄ (0.011 h^-1) in ICPB protocol.The electrical energy per order required for removal of tetracycline hydrochloride in the ICPB protocol exhibited the lowest value for BiVO₄/rGO-HC among the tested materials and treatment protocols. These results highlight the importance of photoelectron shunting in enhancing efficiency of ICPB by engineering graphene at the interface of photocatalyst and biofilm. This unveiled mechanism may serve as an excellent potential in designing energy-efficient ICPB systems targeting wastewater matrices.

中文翻译：

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石墨烯集成紧密耦合光催化生物降解中的界面依赖性电子分流


密切耦合光催化生物降解 （ICPB） 最近被开发为一种高效的废水处理技术，特别是用于去除持久性有机污染物。然而，光催化剂/生物膜在光电子转移方面的相互作用及其对 ICPB 整体性能的影响尚未得到探索。为了研究这些点，制备了钒酸铋和低接触度 （BiVO₄/rGO-LC） 和高接触度 （BiVO₄/rGO-HC） 的还原氧化石墨烯的界面工程复合材料，并将其应用于 ICPB。结果，复合材料显示出与界面相关的光学、结构和电荷载流子分离特性。光电化学测量证实了光催化剂和生物膜之间存在光电子分流，而 BiVO₄/rGO-HC 的电流密度高于 ICPB 协议中的 BiVO₄/rGO-LC 和 BiVO₄（更小的奈奎斯特弧），证实了紧密界面接触对 BiVO₄ 光电子分流的关键作用到生物膜。因此，石墨烯的存在及其界面质量决定了光催化剂和生物膜之间的光电子分流，增强了光电子空穴分离，并与 BiVO₄/rGO-LC （0.013 ^h-1） 和 BiVO₄ （0.011 ^h-1） 相比，实现了对 BiVO₄/rGO-HC （0.031 ^h-1） 的盐酸四环素的优异降解率） 在 ICPB 协议中。在 ICPB 方案中去除盐酸四环素所需的每订单电能在测试材料和处理方案中表现出最低的 BiVO₄/rGO-HC 值。 这些结果强调了光电子分流在通过在光催化剂和生物膜界面处工程石墨烯来提高 ICPB 效率的重要性。这种公开的机制可能在设计针对废水基质的节能 ICPB 系统方面具有极好的潜力。