Boron amplifies the cation vacancy effect to enhance multi-pathway degradation of organic pollutants

In this study, a calcination and boron-doping strategy was developed to construct a metal defect-rich B@Co 1-x S catalyst for Fenton-like reaction. Density functional theory (DFT) calculation and mechanistic investigation confirmed that the enhanced Co vacancies could increase the adsorption of the terminal oxygen in the peroxymonosulfate (PMS) molecules to the surrounding Co atoms, resulting in the activation mechanism by high-valent cobalt-oxygen species (Co(IV)=O), boosting the reaction rate constant by 7.14 times. The B@Co 1-x S/PMS system possessed excellent interference resistance and renewability for efficient degradation of a wide range of contaminants. Moreover, a continuous flow reactor loaded with B@Co 1-x S was developed, which could operate continuously and stably with ciprofloxacin (CIP) removal efficiency above 97 %, proving that the system was promising for applications. Taken all together, this study delved into how to rationally develop cation-deficient transition metal catalysts in Fenton-like systems at the molecular level, which was of critical meaning for wastewater treatment.