Superior Singlet Oxygen Electrosynthesis via Neighboring Dual Molecular Oxygen Coactivation for Selective Tetracycline Detoxification
Kaiyuan Wang, Jie Dai, Guangming Zhan, Long Zhao, Ruizhao Wang, Xingyue Zou, Jiaxian Wang, Qian Zheng, B. Zhou, Rui Zhao, Yan Zhang, Wengao Lian, Yancai Yao, Lizhi Zhang
Abstract
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.