Superior Singlet Oxygen Electrosynthesis via Neighboring Dual Molecular Oxygen Coactivation for Selective Tetracycline Detoxification

Abstract Oxygen (O 2 ) electroreduction offers a green approach for singlet oxygen ( 1 O 2 ) synthesis in wastewater contaminants detoxification. However, traditional single O 2 activation on single‐metal catalytic sites seriously suffers from the kinetically‐unfavorable desorption of adsorbed superoxide species (•O 2 − */•OOH*). Here, we demonstrate a novel dual O 2 coactivation pathway on shortened Fe 1 −O V −Ti sites for superior 1 O 2 electrosynthesis through a rapid disproportionate process between surface‐confined •O 2 − */•OOH*. Theoretical calculations combined with in situ electrochemical spectroscopies demonstrated that the shortened distance between Fe single atom and adjacent unsaturated Ti atom facilitates the direct recombination of surface‐confined Fe−•OOH and Ti−•OO − to yield 1 O 2 , bypassing the formidable •O 2 − */•OOH* desorption process. Impressively, Fe 1 −O V −Ti could realize an excellent 1 O 2 electrosynthesis rate of 54.5 μmol L −1 min −1 with an outstanding 1 O 2 selectivity of 97.6 % under neutral condition, surpassing that of Fe 1 −O−Ti (27.1 μmol L −1 min −1 , 91.7 %). Using tetracycline (TC) as a model pollutant, the resulting Fe 1 −O V −Ti electrode achieved nearly 100 % degradation in 120 min at −0.6 V, meanwhile preventing the generation of toxic intermediates. This study provides a new 1 O 2 electrosynthesis strategy by controlling the distance of adjacent catalytic sites for the coactivation of dual molecular oxygen.