Generating dual-active species by triple-atom sites through peroxymonosulfate activation for treating micropollutants in complex water.

The peroxymonosulfate (PMS)-triggered radical and nonradical active species can synergistically guarantee selectively removing micropollutants in complex wastewater; however, realizing this on heterogeneous metal-based catalysts with single active sites remains challenging due to insufficient electron cycle. Herein, we design asymmetric Co-O-Bi triple-atom sites in Co-doped Bi2 O2 CO3 to facilitate PMS oxidation and reduction simultaneously by enhancing the electron transfer between the active sites. We propose that the asymmetric Co-O-Bi sites result in an electron density increase in the Bi sites and decrease in the Co sites, thereby PMS undergoes a reduction reaction to generate SO4 •- and •OH at the Bi site and an oxidation reaction to generate 1 O2 at the Co site. We suggest that the synergistic effect of SO4 •- , •OH, and 1 O2 enables efficient removal and mineralization of micropollutants without interference from organic and inorganic compounds under the environmental background. As a result, the Co-doped Bi2 O2 CO3 achieves almost 99.3% sulfamethoxazole degradation in 3 min with a k-value as high as 82.95 min-1 M-1 , which is superior to the existing catalysts reported so far. This work provides a structural regulation of the active sites approach to control the catalytic function, which will guide the rational design of Fenton-like catalysts.