Mechanism of anodic activation of chloride to generate singlet oxygen for fast organic removal using an innovative anode

Electrochemical persulfate activation (E-PS) has recently emerged as a highly effective advanced oxidation process in water decontamination . However, the presence of chloride ions (Cl − ) in waters can accelerate anodic corrosion as well as lead to the formation of toxic chlorinated byproducts (i.e., ClO 4 − ), limiting its practical application. In this study, we introduce a novel Nd/Bi@SnO 2 anode to construct E-PS, which exhibits high stability in chloride-containing water with a long-expected service lifetime of 13.7 years. The Nd/Bi@SnO 2 electrode can effectively convert Cl − to reactive chlorine with the assistance of PMS , triggering singlet oxygen ( 1 O 2 ) generation for superior organic removal while avoiding toxic chlorinated byproducts (i.e., ClO 4 − ) generation as well as greatly reducing the energy consumption. Comprehensive structural and electrochemical characterization results demonstrate Nd/Bi co-doping introduces oxygen vacancy on Nd/Bi@SnO 2 , enabling the anode with high oxygen evolution potential , excellent conductivity and superior stability. Scavenging experiments and electron paramagnetic resonance illustrate the generation of various reactive species in the system, among which 1 O 2 predominantly contributes to organic removal and results in harmless intermediates. This innovative approach transforms Cl − into ROSs for eco-friendly, energy-efficient water decontamination.