Shorten migration distance of ROS and accelerate electron transfer by engineering dual Lewis acid sites for synergistic activation of PMS toward rapid TC degradation

Abstract

Shortening the migration distance of reactive oxygen species (ROS) and accelerating electron transfer are promising strategies for boosting the performance of catalysts to activate peroxymonosulfate (PMS). Herein, metallic Lewis acid and non-metallic Lewis acid co-doped graphitic carbon nitride (Co,B-C3N4) are successfully prepared by one-step calcination for synergistically enhanced PMS activation. Cobalt sites significantly accelerated the electron transfer process. Boron acts as an adsorption site for the contaminants, extensively reducing the distance that ROS needs to migrate. Therefore, Co,B-C3N4 demonstrates exceptional PMS activation capability, successfully degrading 99% of tetracycline (TC) in just 6 min with a rate constant reaching 0.407 min−1. Moreover, Co,B-C3N4 still displayed outstanding catalytic performance in complex water environments and long-term cycling conditions. Density Functional Theory (DFT) calculation and mechanism studies demonstrated that non-free radical path (direct electron transfer process and 1O2) plays a dominant role. This work provides a feasible strategy for designing PMS activation catalysts.