A novel tandem photoelectrocatalysis (PEC) cell consisting of TiO₂ nanoneedle arrays (TiO₂ NNs/Ti mesh) photoanode and nitrogen-doped carbon dots (NCDs) modified Co₃O₄ photocathode (NCDs/Co₃O₄/Ti mesh) is designed to work at low/no applied voltage. Electrochemical impedance spectroscopy, incident photo-to-current conversion efficiency, and open-circuit voltage confirmed enhancement in the photogenerated charge transfer efficiency and internal photovoltage, which is due to synergistic effect in combination of two photoelectrodes. Under light-emitting diode (LED) light irradiation and cell voltage of 0.4 V, the system represented high activity and stability (0.0527 min⁻¹ after 20 cycles) and energy efficiency (2.09 kWh m⁻³ order⁻¹) for sulfadiazine removal. Based on the main ^•OH-induced reaction, the cooperative operation mechanism of TiO₂ NNs/Ti mesh and NCDs/Co₃O₄/Ti mesh for sulfadiazine degradation was elaborated. Finally, the high performance under real water matrices or real sunlight irradiation without external voltage confirmed the feasibility of this PEC system in practical application for efficient water purification.

一种新型串联光电催化 (PEC) 电池由 TiO ₂纳米针阵列 (TiO ₂ NNs/Ti mesh) 光电阳极和氮掺杂碳点 (NCDs) 修饰的 Co ₃ O ₄光电阴极 (NCDs/Co ₃ O ₄ /Ti mesh)组成设计用于在低/无施加电压下工作。电化学阻抗谱、入射光电流转换效率和开路电压证实了光生电荷转移效率和内部光电压的增强，这是由于两个光电极组合的协同效应。在发光二极管 (LED) 光照射和 0.4 V 电池电压下，该系统表现出高活性和稳定性（0.0527 min ^-120 个循环后）和去除磺胺嘧啶的能量效率（2.09 kWh m ^-3 order ^{-1 ）。}基于主要的^• OH诱导反应，阐述了TiO ₂ NNs/Ti网格和NCDs/Co ₃ O ₄ /Ti网格对磺胺嘧啶降解的协同作用机理。最后，在没有外部电压的真实水基质或真实阳光照射下的高性能证实了该PEC系统在实际应用中高效净化水的可行性。