Photoelectrochemical (PEC) systems have emerged as a prominent renewable energy-based technology for wastewater treatment, offering sustainable advantages such as eliminating dependence on fossil fuels or grid electricity compared to traditional electrochemical treatment methods. However, previous PEC systems often overlook the potential of ions present in wastewater as an alternative to externally applied bias voltage for enhancing carrier separation efficiency. Here we report a bias-free driven ion assisted photoelectrochemical (IAPEC) system by integration of an electron-ion acceptor cathode, which leverages its fast ion-electron coupling capability to significantly enhance the separation of electrons and holes at the photoanode. We demonstrate that Prussian blue analogues (PBAs) can serve as robust and reversible electron-ion acceptors that provide reaction sites for photoelectron coupling cations, thus driving the hole oxidation to produce strong oxidant free radicals at photoanode. Our IAPEC system exhibits superior degradation performance in wastewater containing chloride medium. This indicates that, in addition to the cations (e.g., Na⁺) accelerating the electron transfer rate, the presence of Cl^– ions further enhance efficient and sustainable wastewater treatment. This work highlights the potential of utilizing abundant sodium chloride in seawater as a cost-effective additive for wastewater treatment, offering crucial insights into the use of local materials for effective, low-carbon, and sustainable treatment processes.

光电化学（PEC）系统已成为一种基于可再生能源的废水处理技术，与传统的电化学处理方法相比，具有可持续的优势，例如消除对化石燃料或电网的依赖。然而，以前的 PEC 系统经常忽视废水中存在的离子作为外部施加偏置电压的替代方案以提高载流子分离效率的潜力。在这里，我们报告了一种通过集成电子-离子受体阴极的无偏压驱动离子辅助光电化学（IAPEC）系统，该系统利用其快速离子-电子耦合能力显着增强光电阳极处电子和空穴的分离。我们证明，普鲁士蓝类似物（PBA）可以作为稳定且可逆的电子离子受体，为光电子耦合阳离子提供反应位点，从而驱动空穴氧化，在光阳极产生强氧化剂自由基。我们的 IAPEC 系统在含氯化物介质的废水中表现出卓越的降解性能。这表明，除了阳离子（例如Na ⁺ ）加速电子转移速率之外，Cl ^-离子的存在进一步增强了废水处理的效率和可持续性。这项工作强调了利用海水中丰富的氯化钠作为废水处理的具有成本效益的添加剂的潜力，为使用当地材料进行有效、低碳和可持续的处理过程提供了重要的见解。