Chemical-Energy-Driven Dioxygen Activation in Aqueous Solution: A Green Advanced Oxidation Strategy for Environmental...

Reactive oxygen species (ROS), such as ·OH, ·O2-, and 1O2, play dominant roles in advanced oxidation processes for environmental remediation. Dioxygen activation provides a green route for ROS generation in aqueous systems because molecular oxygen is abundant, inexpensive, and environmentally benign. Compared with photoactivation or electroactivation, chemical-energy-driven activation without external energy input is particularly attractive for low-energy water treatment, especially under conditions where electrical power is limited or natural solar irradiation is unstable. Understanding and controlling chemical-energy-driven dioxygen activation is therefore important for developing sustainable water-treatment technologies that minimize external energy consumption and the handling of concentrated oxidants. This Account focuses on homogeneous and heterogeneous dioxygen activation and discusses the key factors governing activator selection, ROS generation, and contaminant degradation in aqueous environmental remediation. Most reported oxygen activation systems proceed through sequential one-electron reduction, in which O2 is first converted to ·O2- and then further transformed into H2O2 and ·OH. Therefore, ·O2- acts as an intermediate or precursor in systems, whereas 1O2 occurs less frequently. Chemical energy-driven dioxygen activation has been shown to degrade diverse contaminants, including dyes, sulfonamides, nonsteroidal anti-inflammatory drugs, quinolone antimicrobials, benzene, phenolics, and herbicides. To further improve the activation efficiency, three strategies are recommended: introducing oxygen vacancies, constructing gas-liquid-solid triphase reaction interfaces, and anchoring uniformly dispersed active sites on electron-rich supports. Collectively, these insights deepen the mechanistic understanding of dioxygen activation and provide practical design principles for the development of efficient, durable, and low-energy processes for environmental remediation.