Polarized N⁺-Mediated Charge-Transfer State Drives Two-Electron Water Oxidation

Achieving selective two-electron water oxidation (2e^- WOR) for sustainable hydrogen peroxide (H₂O₂₎ synthesis, while suppressing the competing four-electron oxygen evolution (4e^- OER), represents a formidable challenge in artificial photosynthesis. The difficulty lies in the inherent vulnerability of the *OOH intermediate to over-oxidation or disproportionation, which triggers uncontrollable chain side reactions and naturally biases the reaction toward the less selective 4e^- OER pathway. Here, we present a surface-engineering strategy utilizing a ZnCdS₂ photocatalyst functionalized with polarized N⁺ surfactants, enabling molecular-level control over interfacial water oxidation pathways by establishing a charge-transfer (C-T) excited state. The polarized N⁺ centers effectively reconfigure the surface electronic states through molecular-scale polarization, achieving i) precise modulation of hole potentials and ii) stabilization of the *OOH intermediate, thereby promoting a direct 2e^- WOR pathway. Without the use of any sacrificial reagents, this design achieves an exceptional H₂O₂ production rate of 2.37 mmol·g^{- 1}·h^{- 1} (20.26 times of pristine ZnCdS₂) statically and the scalable outlet concentration of 1.61 mM through a serial micro-batch flow reactor. By bridging atomic-level charge control with macroscopic catalytic performance, our work offers a proof-of-concept advance in C-T excited state driven photocatalysis, highlighting how surface electronic states can drive selective multi-electron reactions.