Interfacial electron flux and triphase microenvironment engineering enable selective singlet oxygen generation for photocatalytic water purification

Selective singlet oxygen (¹O₂) generation via photocatalytic O₂ activation offers a promising pathway for sustainable water purification, yet remains hindered by insufficient electron supply and poor control over reactive oxygen species (ROS) pathways. Here, we report a multiscale strategy that integrates interfacial electron flux engineering with a triphase microenvironment to regulate O₂ activation toward a selective non-radical pathway. The S-scheme Fe₂O₃/MoS₂ heterojunction establishes a sustained, directional electron flux, thereby driving highly efficient O₂ reduction. Meanwhile, the hydrogel scaffold constructs a gas–liquid–solid triphase microenvironment that synchronizes O₂ diffusion, pollutant enrich, and interfacial reaction kinetics. This synergistic regulation selectively channels ROS generation toward ¹O₂ while suppressing non-selective radical pathways. As a result, the system achieves rapid pollutant degradation, high tolerance to complex water matrices, and stable operation in continuous-flow conditions. This work provides a general framework for controlling ROS pathways via coupled electronic and microenvironmental engineering in photocatalytic systems.