Carbon-based electrocatalytic dual-membrane system bolsters singlet oxygen production for ultrafast water decontamination

Applying molecular oxygen for organic pollutant degradation: Strategies, mechanisms, and perspectives

Molecular oxygen (O2) is an environmentally friendly, cost-effective, and non-toxic oxidant. Activation of O2 generates various highly oxidative reactive oxygen species (ROS), which efficiently degrade pollutants with minimal environmental impact. Despite extensive research on the application of O2 activation in environmental remediation, a comprehensive review addressing this topic is currently lacking. This review provides an informative overview of recent advancements in O2 activation, focusing on three primary strategies: photocatalytic activation, chemical activation, and electrochemical activation of O2. We elucidate the respective mechanisms of these activation methods and discuss their advantages and disadvantages. Additionally, we thoroughly analyze the influence of oxygen supply, reactive temperature, and pH on the O2 activation process. From electron transfer and energy transfer perspectives, we explore the pathways for ROS generation during O2 activation. Finally, we address the challenges faced by researchers in this field and discuss future prospects for utilizing O2 activation in pollution control applications. This detailed analysis enhances our understanding and provides valuable insights for the practical implementation of organic pollutant degradation.

Electrocatalytic Generation of Singlet Oxygen via ROS-Mediated Redox Chain Reaction for Efficient Disinfection

The risk of harmful microorganisms to ecosystems and human health has stimulated exploration of singlet oxygen (1O2)-based disinfection. It can be potentially generated via an electrocatalytic process, but is limited by the low production yield and unclear intermediate-mediated mechanism. Herein, we designed a two-site catalyst (Fe/Mo-N/C) for the selective 1O2 generation. The Mo sites enhance the generation of 1O2 precursors (H2O2), accompanied by the generation of intermediate •HO2/•O2-. The Fe site facilitates activation of H2O2 into •OH, which accelerates the •HO2/•O2- into 1O2. A possible mechanism for promoting 1O2 production through the ROS-mediated chain reaction is reported. The as-developed electrochemical disinfection system can kill 1 × 107 CFU mL-1 of E. coli within 8 min, leading to cell membrane damage and DNA degradation. It can be effectively applied for the disinfection of medical wastewater. This work provides a general strategy for promoting the production of 1O2 through electrocatalysis and for efficient electrochemical disinfection.