As the rapid development of oxygen evolution catalysts (OECs) for photoanodes, the issue of charge transfer at the interface of OEC and semiconductor, which becomes the key challenge for the photoelectrochemical (PEC) efficiency, has been rarely addressed and should be taken seriously. Herein, a novel charge transfer system for PEC water oxidation is designed by inserting MXene nanosheets (MNs) between α-Fe₂O₃ and OEC. In this system, MNs act as the hole transfer mediators to efficiently suppress the interfacial charge recombination owing to the high hole mobility of MNs and the formation of built-in electric field at the MNs/α-Fe₂O₃ junction. Meanwhile, the OEC layers, in turn, can protect the MNs from oxidation to achieve prominent stability. The optimized photoanode of Co-Pi/MNs/α-Fe₂O₃ can achieve a remarkable photocurrent density, up to 3.20 mA cm⁻² at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination. An impressive cathodic onset potential shift of ∼250 mV is obtained on Co-Pi/MNs/α-Fe₂O₃ compared with the pristine α-Fe₂O₃. Furthermore, this strategy is also applicable to other photoanode materials, such as BiVO₄, WO₃ and ZnO, verifying the versatility by utilizing the MNs as hole transfer mediators for efficient photogenerated charge separation to enhance the PEC water oxidation.

随着用于光阳极的析氧催化剂（OEC）的快速发展，OEC和半导体界面处的电荷转移问题已成为光电化学（PEC）效率的关键挑战，但很少被解决，应该认真对待。在此，通过在 α-Fe ₂ O ₃和 OEC之间插入 MXene 纳米片 (MNs)，设计了一种用于 PEC 水氧化的新型电荷转移系统。在该系统中，由于 MNs 的高空穴迁移率和在 MNs/α-Fe ₂ O ₃处形成的内建电场，MNs 作为空穴转移介体有效抑制界面电荷复合交界处。同时，OEC 层反过来可以保护 MNs 免受氧化以实现显着的稳定性。优化的 Co-Pi/MNs/α-Fe ₂ O ₃光阳极可实现显着的光电流密度，在 AM 1.5 G 照明下，在 1.23 V 与可逆氢电极 (RHE) 下高达 3.20 mA cm ^-2。与原始的α-Fe ₂ O ₃相比，Co-Pi/MNs/α-Fe ₂ O ₃获得了令人印象深刻的~250 mV 的阴极起始电位漂移。此外，该策略也适用于其他光阳极材料，如 BiVO ₄、WO ₃ 和 ZnO，通过利用 MN 作为空穴转移介质进行有效的光生电荷分离以增强 PEC 水氧化，验证了多功能性。